As a first result the author dismisses Lange's method as hopeless: the results in successive determinations on the same materials showing variations up to 60 p.ct. The results by c and d are satisfactorily concordant: the yields of cellulose are higher than of 'crude fibre.' This is obviously due to the conservation of 'hemicellulose' products, which are hydrolysed and dissolved in the treatments for 'crude fibre' estimation. A modified method was next investigated, in which the process of digestion with acid chloroxy- compounds (c and d) was preceded by a treatment with boiling dilute acid. The yields of cellulose by this method (e) are more uniform, and show less divergence from the numbers for 'crude fibre.'

The author's numerical results are given in a series of tables which include determinations of proteids and ash constituents, and the corresponding deductions from the crude weight in calculating to 'pure cellulose.' The subjoined extract will illustrate these main lines of investigation.

___________ Crude Fibre Pure Cellulose ___ _____ Raw Material Weende Hoffmeister Hoffmeister, Method. Method. modified by (a) (c) Author. (e) ___ ___ ___ ___ Oat grass 30.35 34.9 31.5 Lucerne 25.25 28.7 20.5 Leaves of ash 13.05 15.4 13.8 Roots of melic 21.60 29.1 21.4 Coffee beans 18.30 35.1 23.3 Bran 8.2 19.3 9.3 ___ ___ ___ ___

The final conclusion drawn from these results is that the method of Hoffmeister yields a product containing variable proportions of hemicelluloses. These are eliminated by boiling with a dilute acid (1.25 p.ct. H{2}SO{4}), which treatment may be carried out on the raw material—i.e. before exposure to the acid chlorate, or on the crude cellulose as ordinarily isolated.

Determination of Tissue-constituents.—By the regulated action of certain solvents applied in succession, it appears that such constituents of the plant-complex can be removed as have no organic connection with the cellular skeleton: the residue from such treatments, conversely, fairly represents the true tissue-constituents. The author employs the method of digestion with cold dilute alkaline solutions (0.15 to 0.5 p.ct. NaOH), followed by exhaustive washing with cold and hot water, afterwards with cold and hot alcohol, and finally with ether.

The residue is dried and weighed as crude product. When necessary, the proportions of ash and proteid constituents are determined and deducted from the 'crude product' which, thus corrected, may be taken as representing the 'carbohydrate' tissue constituents.

Determination of Hemicelluloses.—By the process of boiling with dilute acids (1.25 p.ct. H{2}SO{4}) the hemicelluloses are attacked—i.e. hydrolysed and dissolved. The action of the acid though selective is, of course, not exclusively confined to these colloidal carbohydrates. The proteid and mineral constituents are attacked more or less, and the celluloses themselves are not entirely resistant to the action. The loss due to the latter may be neglected, but in calculating the hemicellulose constants from the gross loss the proteids and mineral constituents require to be taken into account in the usual way.

QUANTITATIVE SEPARATION OF HEMICELLULOSE, CELLULOSE, AND LIGNIN. PRESENCE OF PENTOSANES IN THESE SUBSTANCES.

WILHELM HOFFMEISTER (Landw. Versuchs-Stat, 1898, 50, 347-362).

(p. 88) The separation of the cellulose-like carbohydrates of sunflower husks is described.

In order to ascertain the effect of dilute ammonia on the cellulose substances of lignin, a dried 5 p.ct. caustic soda extract was extracted successively with 1, 2, 3, and 4 p.ct. sodium hydroxide solution. Five grams of the 2 p.ct. extract were then subjected to the action of ammonia vapour; the cellulose did not completely dissolve in six weeks. Cellulose insoluble in caustic soda (32 grms.) was next extracted with ammonia, in a similar manner, for 10 days, dried, and weighed. 30.46 grms. remained, which, when treated with 5 p.ct. aqueous caustic soda, yielded 0.96 grm. (3 per cent.) of hemicellulose.

When cellulose is dissolved in Schweizer's solution, the residue is, by repeated extraction with aqueous sodium hydroxide, completely converted into the soluble form. On evaporating the ammonia from the Schweizer's extract, at the ordinary temperature and on a water-bath respectively, different amounts of cellulose are obtained; more hemicellulose is obtained, by caustic soda, from the heated solution than from that which was not heated. In this operation the pentosanes are more influenced than the hexosanes; pentosanes are not always readily dissolved by caustic soda, and hexosanes are frequently more or less readily dissolved. Both occur in lignin, and are then undoubtedly indigestible. These points have to be considered in judging the digestibility of these carbohydrates.

A comparison of analyses of clover, at different periods, in the first and second years of growth, shows that both cellulose (Schweizer's extract) and lignin increase in both constituents. In the second year the lignin alone increased to the end; the cellulose decreased at the end of June. In the first year it seemed an absolutely as well as relatively greater amount of cellulose, and lignin was produced in the second year; this, however, requires confirmation. The amount of pentosanes in the Schweizer extract was relatively greater in the second than in the first year, but decreased in the lignin more in the second year than in the first: this result is also given with reserve.

DIE CONSTITUTION DER CELLULOSEN DER CEREALIEN.

C. F. CROSS, E. J. BEVAN, and C. SMITH (Berl. Ber., 1896, 1457).

THE CONSTITUTION OF THE CEREAL CELLULOSES.

(p. 84) Straw cellulose is resolved by two methods of acid hydrolysis into a soluble furfural-yielding fraction, and an insoluble fraction closely resembling the normal cellulose. (a) The cellulose is dissolved in sulphuric acids of concentration, H{2}SO{4}.2H{2}O, H{2}SO{4}.3H{2}O. As soon as solution is complete, the acid is diluted. A precipitate of cellulose hydrate (60-70 p.ct.) is obtained, and the filtered solution contains 90-95 p.ct. of the furfuroids of the original cellulose. The process is difficult to control, however, in mass, and to obtain the latter in larger quantity the cellulose (b) is digested with six times its weight of 1 p.ct. H{2}SO{4} at 3 atm. pressure, the products of the action being (1) a disintegrated cellulose retaining only a small fraction (1/12) of the furfural-yielding groups, and (2) a slightly coloured solution of the hydrolised furfuroids. An investigation of the latter gave the following results: By oxidation with nitric acid no saccharic acid was obtained; showing the absence of dextrose. The numbers for cupric reduction were in excess of those obtained with the hexoses. The yield of ozazone was high, viz. 30 to 40 p.ct. of the weight of the carbohydrate in solution. On fractionating, the melting-points of the fractions were found to lie between 146 deg. and 153 deg.. Ultimate analysis gave numbers for C, H, and N identical with those of a pentosazone. The product of hydrolysis appears, therefore, to be xylose or a closely related derivative.

All attempts to obtain a crystallisation of xylose from the solution neutralised (BaCO_{3}), filtered, and evaporated, failed. The reaction with phloroglucol and HCl, moreover, was not the characteristic red of the pentoses, but a deep violet. The product was then isolated as a dry residue by evaporating further and drying at 105 deg.. Elementary analysis gave the numbers C 44.2, 44.5, and H 6.7, 6.3. Determinations of furfural gave 39.5 to 42.5 p.ct. On treating the original solution with hydrogen peroxide, and warming, oxidation set in, with evolution of CO_{2}. This was estimated (by absorption), giving numbers for CO_{2}, 19.5, 20.5, 20.1 p.ct. of the substance.

The sum of these quantitative data is inconsistent with a pentose or pentosane formula; it is more satisfactorily expressed by the empirical formula

O / C{5}H{8}O{3} CH{2}, / O

which represents a pentose monoformal. Attempts to synthesise a compound of this formula have been so far without success.

UEBER EINIGE CHEMISCHE VORGAeNGE IN DER GERSTENPFLANZE.

C. F. CROSS, E. J. BEVAN, and C. SMITH (Berl. Ber., 1895, 2604).

THE CHEMICAL LIFE-HISTORY OF THE BARLEY PLANT.

(p. 84) Owing to the presence of 'furfuroids' in large proportion as constituents of the tissues of the stems of cereals, these plants afford convenient material for studying the problem of the constitution of the tissue-furfuroids, as well as their relationship to the normal celluloses. The growing barley plant was investigated at successive periods of growth. Yield of furfural was estimated on the whole plant and on the residue from a treatment with alkaline and acid solvents in the cold such as to remove all cell contents. This residue is described as 'permanent tissue.' The observations were carried out through two growing seasons—1894-5—which were very different in character, the former being rainy with low temperature, the latter being abnormal in the opposite direction, i.e. minimum rainfall and maximum sunshine. The barley selected for observation was that of two experimental plots of the Royal Agricultural Society's farm, one (No. 1) remaining permanently unmanured, and showing minimum yield, the other (No. 6) receiving such fertilising treatment as to give maximum yields.

The numerical results are given in the annexed tables:

Table Headings:

A: Date B: Age of Crop C: Plot D: Dry Weight E: Furfural p.ct. of dry weight (a) F: Permanent tissue p.ct. dry weight G: Furfural from permanent tissue H: P.ct. of tissue I: P.ct. of entire plant J: Ratio a : c

BARLEY CROP, WOBURN, 1894.

____________ [G] ___ [A] [B] [C] [D] [E] [F] [H] [I] [J] __ __ __ _ _ _ _ _ __ May 7 6 weeks 1 19.4 7.0 53.4 12.7 6.8 1.03 : 1 6 14.7 7.0 55.9 10.3 5.7 1.23 : 1 June 4 10 weeks 1 17.6 7.7 52.9 11.6 6.1 1.26 : 1 6 13.5 8.1 58.5 13.4 7.8 1.04 : 1 July 10 15 weeks 1 42.0 9.0 65.7 9.8 6.4 1.40 : 1 6 32.9 10.6 65.7 12.5 8.2 1.30 : 1 Cut 21 weeks 1 64.0 11.9 70.0 14.5 10.1 1.18 : 1 Aug. 21 6 64.6 13.4 70.5 15.0 10.6 1.26 : 1 Carried 22 weeks 1 84.0 12.7 75.0 16.5 12.4 1.02 : 1 Aug. 31 6 86.4 12.4 78.4 15.1 11.8 1.05 : 1 BARLEY CROP, WOBURN, 1895. May 15 7 weeks 1 20.6 6.6 53.9 10.2 5.5 1.20 : 1 6 17.8 5.8 56.7 9.6 5.4 1.07 : 1 June 18 12 weeks 1 34.6 8.0 38.2 14.7 5.6 1.42 : 1 6 33.4 7.6 44.5 15.0 6.7 1.14 : 1 July 16 16 weeks 1 52.8 12.1 55.6 16.3 9.1 1.33 : 1 6 54.4 10.6 46.2 19.1 8.8 1.20 : 1 Aug. 16 20 weeks 1 66.8 9.2 49.1 17.0 8.3 1.10 : 1 6 65.0 9.8 49.8 19.1 9.4 1.04 : 1 Sept. 3 22 weeks 1 84.3 10.4 45.7 17.6 8.0 1.31 : 1 6 86.3 10.2 45.3 17.3 7.8 1.30 : 1 __ __ __ _ _ _ _ _ __

The variations exhibited by these numbers are significant. It is clear, on the other hand, that the assimilation of the furfuroids does not vary in any important way with variations in conditions of atmosphere and soil nutrition. They are essentially tissue-constituents, and only at the flowering period is there any accumulation of these compounds in the alkali-soluble form. It has been previously shown (ibid. 27, 1061) that the proportion of furfuroids in the straw-celluloses of the paper-maker differs but little from that of the original straws. For the isolation of the celluloses the straws are treated by a severe process of alkaline hydrolysis, to which, therefore, the furfuroid groups offer equal resistance with the normal hexose groups with which they are associated in the complex.

The furfuroids of the cereal straws are therefore not pentosanes. They are original products of assimilation, and not subject to secondary changes after elaboration such as to alter either their constitution or their relationship to the normal hexose groups of the tissue-complex.

(1) CONSTITUTION OF THE CEREAL CELLULOSES

(Chem. Soc. J. 1896, 804).

(2) THE CARBOHYDRATES OF BARLEY STRAW

(Chem. Soc. J. 1896, 1604).

(3) THE CARBOHYDRATES OF THE CEREAL

STRAWS (Chem. Soc. J. 1897, 1001).

(4) THE CARBOHYDRATES OF BARLEY STRAW

(Chem. Soc. J. 1898, 459).

C. F. CROSS, E. J. BEVAN, and CLAUD SMITH.

These are a series of investigations mainly devoted to establishing the identity of the furfural-yielding group which is a characteristic constituent.

This 'furfuroid' while equally resistant to alkalis as the normal cellulose group with which it is associated, is selectively hydrolysed by acids. Thus straw cellulose dissolves in sulphuric acids of concentration H{2}SO{4}.2H{2}O - H{2}SO{4}.3H{2}O, and on diluting the normal cellulose is precipitated as a hydrate, and the furfuroid remains in solution. But this sharp separation is difficult to control in mass. By heating with a very dilute acid (1 p.ct. H{2}SO{4}) the conditions are more easily controlled, the most satisfactory results being obtained with 15 mins. heating at 3 atm. pressure.

(1) Operating in this way upon brewers' grains the furfuroid was obtainable as the chief constituent of a solution for which the following experimental numbers were determined:—Total dissolved solids, 28.0 p.ct. of original 'grains'; furfural, 39.5 p.ct. of total dissolved solids, as compared with 12.5 p.ct. of total original grains; cupric reduction (calc. to total solids), 110 (dextrose = 100) osazone; yield in 3 p.ct. solution, 35 p.ct. of weight of total solids.

Pentosazone Analysis N 17.1 17.3 17.07 C 62.5 62.3 62.2 H 6.4 6.5 6.1 Melting-point 146 deg.-153 deg.

From these numbers it is seen that of the total furfuroids of the original 'grains' 84 p.ct. are thus obtained in solution in the fully hydrolysed form, which is that of a pentose or pentose derivative. It was, however, found impossible to obtain any crystallisation from the neutralised (BaCO_{3}) and concentrated solution, the syrup being kept for some weeks in a desiccator. It was noted at the same time that the colour reaction of the original solution with phloroglucol and hydrochloric acid was a deep violet, in contradistinction to the characteristic red of the pentoses. On oxidation with hydrogen peroxide, in the proportion of 1 mol. H_{2}O_{2} to 1 mol. of the carbohydrate in solution, carbonic anhydride was formed in quantity = 20.0 p.ct. of the latter.

Fermentation (yeast) experiments also showed a divergence from the resistant behaviour of the pentoses, a considerable proportion of the furfuroid disappearing in a normal fermentation.

(2) The quantitative methods above described were employed in investigating the barley plant at different stages of its growth. The green plant was extracted with alcohol, the residue freed from alcohol and subjected to acid hydrolysis.

The hydrolysed extract was neutralised and fermented. In the early stages of growth the furfuroids were completely fermented, i.e. disappeared in the fermentation. In the later stages this proportion fell to 50 p.ct. In the earlier stages, moreover, the normal hexose constituents of the permanent tissue were hydrolysed in large proportion by the acid, whereas in the matured straw the hydrolysis is chiefly confined to the furfuroids. In the early stages also the permanent tissue yields an extract with relatively low cupric reduction, showing that the carbohydrates are dissolved by the acid in a more complex molecular condition.

These observations confirm the view that the furfuroids take origin in a hexose-pentose series of transformations. The proportion of furfuroid groups to total carbohydrates varies but little, viz. from 1/3 in the early stages to a maximum of 1/4 at the flowering period. At this period the differentiation of the groups begins to be marked.

Taking all the facts of (1) and (2), they are not inconsistent with the hypothesis of an internal transformation of a hexose to a pentose-monoformal. Such a change of position and function of oxygen from OH to CO within the group —CH.OH— is a species of internal oxidation which reverses the reduction of formaldehyde groups in synthesising to sugars, and appears therefore of probable occurrence.

These constitutional problems are followed up in (3) by the indirect method of differentiating the relationships of these furfuroids to yeast fermentation, from those of the pentoses. Straw and esparto celluloses are subjected to the processes of acid hydrolysis, and the neutralised extracts fermented. With high furfural numbers indicating that the furfuroids are the chief constituents of the extract, there is an active fermentation with production of alcohol. The cupric reduction falls in greater ratio to the original (unfermented) than the furfural. Observations on the pure pentoses—xylose and arabinose added to dextrose solutions, and then exposed to yeast action—show that in a vigorous fermentation not unduly prolonged the pentoses are unaffected, but that they do come within the influence of the yeast-cell when the latter is in a less vigorous condition, and when the hexoses are not present in relatively large proportion.

(4) The observations on the growing plant were resumed with the view of artificially increasing the differentiation of the two main groups of carbohydrates. From a portion of a barley crop the inflorescence was removed as soon as it appeared. The crop was allowed to mature, and a full comparison instituted between the products of normal and abnormal growth. With a considerable difference in 'permanent tissue' (13 p.ct. less) and a still greater defect in cellulose (24 p.ct.), the constants for the furfuroids in relation to total carbohydrates were unaffected by the arrested development. This was also true of the behaviour of the hydrolysed extracts (acid processes) to yeast fermentation.

(5) The extract obtained from the brewers' grains by the process described in (2) was investigated in relation to animal digestion. It has been now generally established that the furfuroids as constituents of fodder plants are digested and assimilated in large proportion in passing through animal digestive tracts, and in this respect behave differently from the pentoses. The furfuroids being obtained, as described, in a fully hydrolysed condition (monoses) the digestion problem presented itself in a new aspect, and was therefore attacked.

The result of the comparative feeding experiments upon rabbits was to show that in this previously hydrolysed form the furfuroids are almost entirely digested and assimilated, no pentoses, moreover, appearing in the urine.

Generally we may sum up the present solution of the problem of the relationship of the furfuroids to plant assimilation and growth as follows:—The pentoses are not produced as such in the process of assimilation; but furfural-yielding carbohydrates are produced directly and in approximately constant ratio to the total carbohydrates; they are mainly located in the permanent tissue; in the secondary changes of dehydration, &c., accompanying maturation they undergo such differentiation that they become readily separable by processes of acid hydrolysis from the more resistant normal celluloses; but in relation to alkaline treatments they maintain their intimate union with the latter. They are finally converted into pentoses by artificial treatments, and into pentosanes in the plant, with loss of 1 C atom in an oxidised form. The mechanism of this transformation of hexoses into pentoses is not cleared up. It is independent of external conditions, e.g. fertilisation and atmospheric oxidations, and is probably therefore a process of internal rearrangement of the character of an oxidation.

ZUR KENNTNISS DER IN DEN MEMBRANEN DER PILZE ENTHALTENEN BESTANDTHEILE.

E. WINTERSTEIN (Ztschr. Physiol. Chem., 1894, 521; 1895, 134).

ON THE CONSTITUENTS OF THE TISSUE OF FUNGI.

(p. 87) These two communications are a contribution of fundamental importance, and may be regarded as placing the question of the composition of the celluloses of these lowest types on a basis of well-defined fact. In the first place the author gives an exhaustive bibliography, beginning with the researches of Braconnot (1811), who regarded the cellular tissue of these organisms as a specialised substance, which he termed 'fungin.' Payen rejects this view, and regards the tissue, fully purified by the action of solvents, as a cellulose (C_{6}H_{10}O_{5}). This view is successively supported by Fromberg [Mulder, Allg. Phys. Chem., Braunschweig, 1851], Schlossberger and Doepping [Annalen, 52, 106], and Kaiser. De Bary, on a review of the evidence, adopts this view, but, as the purified substance fails to give the characteristic colour-reactions with iodine, he uses the qualifying term 'pilzcellulose' [Morph. u. Biol. d. Pilze u. Flechten, Leipzig, 1884].

C. Richter, on the other hand, shows that these reactions are merely a question of methods of purification or preparation [Sitzungsber. Acad. Wien, 82, 1, 494], and considers that the tissue-substance is an ordinary cellulose, with the ordinary reactions masked by the presence of impurities. In regard to the lower types of fungoid growth, such as yeast, the results of investigators are more at variance. The researches of Salkowski (p. 113) leave little doubt, however, that the cell-membrane is of the cellulosic type.

The author's researches extend over a typical range of products obtained from Boletus edulis, Agaricus campestris, Cantharellus cibarius, Morchella esculenta, Polyporus officinalis, Penicillium glaucum, and certain undetermined species. The method of purification consisted mainly in (a) exhaustive treatments with ether and boiling alcohol, (b) digestion with alkaline hydrate (1-2 p.ct. NaOH) in the cold, (c) acid hydrolysis (2-3 p.ct. H{2}SO{4}) at 95 deg.-100 deg., followed by a chloroxidation treatment by the processes of Schulze or Hoffmeister, and final alkaline hydrolysis.

The products, i.e. residues, thus obtained were different in essential points from the celluloses isolated from the tissues of phanerogams similarly treated. Only in exceptional cases do they give blue reactions with iodine in presence of zinc chloride or sulphuric acid. The colourations are brown to red. They resist the action of cuprammonium solutions. They are for the most part soluble in alkaline hydrate solution (5-10 p.ct. NaOH) in the cold. They give small yields (1-2 p.ct.) of furfural on boiling with 10 p.ct. HCl.Aq.

Elementary analyses gave the following results, which are important in establishing the presence of a notable proportion of nitrogen, which has certainly been overlooked by the earlier observers:—

'Cellulose' or residue from C H N Boletus edulis (Schulze process) 42.4 6.5 3.9 Boletus edulis (Hoffmeister process) 44.6 6.3 3.6 Polyporus off. 43.7 6.5 0.7 Cantharellus cib. 44.9 6.8 3.0 Agaricus campestris 44.3 6.6 3.6 Botrytis 42.1 6.3 3.9 Penicillium glaucum 3.3 Morchella esculenta 2.5

It is next shown that this residual nitrogen is not in the form of residual proteids (1) by direct tests, all of which gave negative results, and (2) indirectly by the high degree of resistance to both alkaline and acid hydrolysis. The 'celluloses' are attacked by boiling dilute acids (1 p.ct. H{2}SO{4}), losing in weight from 10 to 23 p.ct., the dissolved products having a cupric reduction value about 50 p.ct. that of an equal weight of dextrose. As an extreme hydrolytic treatment the products were dissolved in 70 p.ct. H{2}SO{4}, allowed to stand 24 hours, then considerably diluted (to 3 p.ct. H{2}SO{4}) and boiled to complete the inversion. The yields of glucose, calculated from the cupric reduction, were as follows:—

Boletus edulis 65.2 p.ct. Polyporus off. 94.7 " Agaricus campestris 59.1 " Morchella esculenta 60.1 " Cantharellus cib. 64.9 " Botrytis 60.8 "

It will be noted that the exceptionally high yield from the Polyporus cellulose is correlated with its exceptionally low nitrogen. By actual isolation of a crystalline dextrorotary sugar, by preparations of osazone and conversion into saccharic acid, it was proved that dextrose was the main product of hydrolysis. The second main product was shown to be acetic acid, the yield of which amounted to 8 p.ct. in several cases.

Generally, therefore, it is proved that the more resistant tissue constituents of the fungi are not cellulose, but a complex of carbohydrates and nitrogenous groups in combination, the former being resolved into glucoses by acid hydrolysis, and the latter yielding acetic acid as a characteristic product of resolution together with the nitrogenous groups in the form of an uncrystallisable syrup.

In the further prosecution of these investigations (2) the author proceeded from the supposition of the identity of the nitrogenous complex of the original with chitin, and adopted the method of Ledderhose (Ztschr. Physiol. Chem. 2, 213) for the isolation of glucosamin hydrochloride, which he succeeded in obtaining in the crystalline form. In the meantime E. Gilson had shown that these tissue substances in 'fusion' with alkaline hydrates yield a residue of a nitrogenous product (C{14}H{28}N{2}O{10}), which is soluble in dilute acids [Recherches Chim. sur la Membrane Cellulaire des Champignons, La Cellule, v. II, pt. 1]. This residue, which was termed mycosin by Gilson, has been similarly isolated by the author. It is proved, therefore, that the tissues of the fungi do contain a product resembling chitin. [See also Gilson, Compt. Rend. 120, 1000.] This constituent is in intimate union with the carbohydrate complex, which is resolved similarly to the hemicelluloses. Various intermediate terms of the hydrolytic series have been isolated. But the only fully identified product of resolution is the dextrose which finally results.

UEBER DIE KOHLENHYDRATE D. HEFE.

E. SALKOWSKI (Berl. Ber., 27, 3325).

ON THE CARBOHYDRATES OF YEAST.

The author has isolated the more resistant constituents of the cell-membrane by boiling with dilute alkalis, and exhaustively purifying with alcohol and ether.

The residue was only a small percentage (3-4 p.ct) of the original, and retained only 0.45 p.ct. N.

It was heated in a digester with water at 2-3 atm. steam-pressure, and thus resolved into approximately equal portions of soluble cellulose (a) and insoluble (b). The latter, giving no colour-reaction with iodine, is termed achroocellulose; the former reacts, and is therefore termed erythrocellulose. The former is easily separated from its opalescent solution. It has the empirical composition of cellulose. In the soluble form it resembles glycogen. The achroocellulose is isolated in the form of horny or agglomerated masses. It appears to be resolved by ultimate hydrolysis into dextrose and mannose.



SECTION V. FURFUROIDS, i.e. PENTOSANES AND FURFURAL-YIELDING CONSTITUENTS GENERALLY

(1) Reactions of the Carbohydrates with Hydrogen Peroxide.

C. F. CROSS, E. J. BEVAN, and CLAUD SMITH (J. Chem. Soc., 1898, 463).

(2) Action of Hydrogen Peroxide on Carbohydrates in the Presence of Ferrous Salts.

R. S. MORRELL and J. M. CROFTS (J. Chem. Soc., 1899, 786).

(3) Oxidation of Furfuraldehyde by Hydrogen Peroxide.

C. F. CROSS, E. J. BEVAN, and T. HEIBERG (J. Ch. Soc., 1899, 747).

(4) EINWIRKUNG VON WASSERSTOFFHYPEROXID AUF UNGESAeTTIGTE KOHLENWASSERSTOFFE.

C. F. CROSS, E. J. BEVAN, and T. HEIBERG (Berl. Ber., 1900, 2015).

ACTION OF HYDROGEN PEROXIDE ON UNSATURATED HYDROCARBONS.

The above series of researches grew out of the observations incidental to the use of the peroxide on an oxidising agent in investigating the hydrolysed furfuroids (102). Certain remarkable observations had previously been made by H. J. H. Fenton (Ch. Soc. J., 1894, 899; 1895, 774; 1896, 546) on the oxidation of tartaric acid by the peroxide, acting in presence of ferrous salts, the —CHOH—CHOH— residue losing H_{2} with production of the unsaturated group, —OH.C=C.OH—. These investigations have subsequently been considerably developed and generalised by Fenton, but as the results have no immediate bearing on our main subject we must refer readers to the J. Chem. Soc., 1896-1900.

From the mode of action diagnosed by Fenton it was to be expected that the CHOH groups of the carbohydrates would be oxidised to CO groups, and it has been established by the above investigations (1) and (2) that the particular group to be so affected in the hexoses is that contiguous to the typical

CO

group. There results, therefore, a dicarbonyl derivative ('osone'), which reacts directly with 2 mol. phenyl hydrazine in the cold to form an osazone. This was directly established for glucose, laevulose, galactose, and arabinose (2). While this is the main result, the general study of the product shows that the oxidation is not simple nor in direct quantitative relationship to the H{2}O{2} employed. The molecular proportion of the aldoses affected appears to be in considerable excess, and the reaction is probably complicated by interior rearrangement.

In the main, the original aldehydic group resists the oxidation. But a certain proportion of acid products are formed, probably tartronic acid. On distillation with condensing acids a large proportion of volatile monobasic acids (chiefly formic) are obtained. The proportion of furfural obtained amounts to 3-4 per cent. of the weight of the original carbohydrate.

Since the general result of these oxidations is the substitution of an OH group for an H atom, it was of interest to determine the behaviour of furfural with the peroxide. The oxidation was carried out in dilute aqueous solution of the aldehyde at 20 deg.-40 deg., using 2-3 mols. H_{2}O_{2} per 1 mol. C_{5}H_{4}O_{2}. The main product is a hydroxyfurfural, which was separated as a hydrazone. A small quantity of a monobasic acid was formed, which was identified as a hydroxypyromucic acid. Both aldehyde and acid appear to be the alpha beta derivatives. The aldehyde gives very characteristic colour reactions with phloroglucinol and resorcinol in presence of hydrochloric acid, which so closely resemble those of the lignocelluloses that there is little doubt that these particular reactions must be referred to the presence of the hydroxyfurfural as a normal constituent.

The study of these oxidations was then extended to typical unsaturated hydrocarbons—viz. acetylene and benzene. (4) From the former the main product was acetic acid, but the attendant formation of traces of ethyl alcohol indicates that the hydrogen of the peroxide may take a direct part in this and other reactions. This view receives some support from the fact that the interaction of the H{2}O{2} with permanganates has now been established to be an oxidation of the H{2} of the peroxide by the permanganate oxidation, with liberation, therefore, of the O{2} of the peroxide as an unresolved molecule [Baeyer].

Benzene itself is also powerfully attacked by the peroxide when shaken with a dilute solution in presence of iron salts. The products are phenol and pyrocatechol, with some quantity of an amorphous product probably formed by condensation of a quinone with the phenolic products of reaction.

* * * * *

These types of oxidation effects now established give a definite significance to the physiological functions of the peroxide, which is a form of 'active oxygen' of extremely wide distribution. It would have been difficult a priori to devise an oxidant without sensible action on aldehydic groups, yet delivering a powerful attack on hydrocarbon rings; or to have suggested a synthesis of the sugars from tartaric acid with a powerful oxidising treatment as the first and essential stage in the transformation.

Our present knowledge of such actions and effects suggests a number of new clues to genetic relationships of carbon compounds within the plant. The conclusion is certainly justified that the origin of the pentoses is referable to oxidations of the hexoses, in which this form of 'active oxygen' plays an important part.

We must note here the researches of O. Ruff, who has applied these oxidations with important results in the systematic investigation of the carbohydrates.

UEBER DIE VERWANDLUNG DER D-GLUCONSAeURE IN D-ARABINOSE (Berl. Ber., 1898, 1573).

CONVERSION OF D-GLUCONIC ACID INTO D-ARABINOSE.

* * * * *

D UND L ARABINOSE (Ibid. 1899, 550).

* * * * *

ZUR KENNTNISS DER OXYGLUCONSAeURE (Ibid. 1899, 2269).

ON OXYGLUCONIC ACID.

Ruff in these researches has realised a simple and direct transition from the hexoses to the pentoses. By oxidising gluconic acid with the peroxide the beta —CHOH— group is converted into carbonyl at the same time that the terminal COOH [alpha] is oxidised to CO_{2}. The yields of the resulting pentose are large. Simultaneously there is formed an oxygluconic acid, which appears to be a ketonic acid of formula —CH_{2}OH.CO.(CHOH)_{3}.COOH—.

From these results we see a further range of physiological probabilities; and with the concurrent actions of oxygen in the forms of or related to hydrogen peroxide on the one side, and ozone on the other, we are able to account in a simple way for the relationships of the 'furfuroid' group, which may include a number of intermediate terms in the hexose-pentose series.

Following in this direction of development of the subject is a study of the action of persulphuric acid upon furfural.

EINWIRKUNG DES CARO'SCHEN REAGENS AUF FURFURAL.

C. F. CROSS, E. J. BEVAN, and J. F. BRIGGS (Berl. Ber., 1900, 3132).

Regarding this reagent as another form of 'active oxygen,' it is important to contrast its actions with those of the hydrogen peroxide. Instead of the beta-hydroxyfurfural (ante, 115) we obtain the delta-aldehyde as the first product. The aldehydic group is then oxidised, and as a result of attendant hydrolysis the ring is broken down and succinic acid is formed, the original aldehydic group of the furfural being split off in the form of formic acid. The reactions take place at the ordinary temperature and with the dilute form of the reagent described by Baeyer and Villiger (Ber. 32, 3625). These results have some special features of interest. The alpha delta-hydroxyfurfural has similar colour reactions to those of the alpha beta-derivative, and may also therefore be present as a constituent of the lignocelluloses. The tendency to attack in the 1.4 position in relation to an aldehydic group further widens the capabilities of 'active oxygen' in the plant cell. Lastly, this is the simplest transition yet disclosed from the succinyl to furfural grouping, being effected by a regulated proportion of oxygen, and under conditions of reaction which may be described as of the mildest. In regard to the wide-reaching functions of asparagin in plant life, we have a new suggestion of genetic connections with the furfuroids.

VERGLEICH DER PENTOSEN-BESTIMMUNGSMETHODEN VERMITTELST PHENYLHYDRAZIN UND PHLOROGLUCIN.

M. KRUeGER (Inaug.-Diss., Goettingen, 1895).

COMPARISON OF METHODS OF ESTIMATING FURFURAL AS HYDRAZONE AND PHLOROGLUCIDE.

The author traces the development of processes of estimating furfural (1) by precipitation with ammonia (furfuramide), (2) by volumetric estimation with standardised phenylhydrazine, (3) by weighing the hydrazone.

In 1893 (Chem. Ztg. 17, 1745) Hotter described a method of quantitative condensation with pyrogallol requiring a temperature of 100 deg.-110 deg. for two hours. The insoluble product collected, washed, dried at 103 deg., and weighed, gives a weight of 1.974 grm. per 1 grm. furfural.

Councler substitutes phloroglucinol for pyrogallol, with the advantage of doing away with the digestion at high temperature. (Ibid. 18, 966.) This process, requiring the presence of strong HCl, has the advantage of being applied directly to the acid distillate, in which form furfural is obtained as a product of condensation of pentoses, &c. A comparative investigation was made, precipitating furfural (a) as hydrazone in presence of acetic acid, and (b) as phloroglucide in presence of HCl (12 p.ct). In (a) by varying the weights of known quantities of furfural, and using the factor, hydrazone x 0.516 [+ 0.0104] in calculating from the weights of precipitates obtained, the maximum variations from the theoretical number were +1.71 and -1.74. In (b) it was found necessary to vary the factor from 0.52 to 0.55 in calculating from phloroglucide to furfural. The greatest total range of variation was found to be 2.5 p.ct. The phenol process is therefore equally accurate, has the advantages above noted, and, in addition, is less liable to error from the pressure in the distillates obtained from vegetable substances of volatile products, e.g. ketonic compounds, accompanying the furfural.

This method has been criticised by Helbel and Zeisel [Sitz.-ber, Wiener Akad. 1895, 104, ii. p. 335] on two grounds of error, viz. (1) the presence of diresorcinol in all ordinary preparations of phloroglucinol, and (2) changes in weight of the precipitate of phloroglucide on drying. The process was carried out comparatively with ordinary preparations, and with specially pure preparations of the phenol. The quantitative results were identical. The criticisms in question are therefore dismissed. Although the process is to be recommended for its simplicity and the satisfactory concordance of results it is to be noted that it rests upon an empirical basis, since the phloroglucide is not formed by the simple reaction 2 [C_{5}H_{4}O_{2} + C_{6}H_{6}O_{3}] - H_{2}O = C_{22}H_{18}O_{9}, but appears to have the composition C_{16}H_{12}O_{6}.

In part ii. of this paper the author discusses the question of the probable extent in the sense of diversity of constitution of furfural-yielding constituents of plant-tissues. Glucoson was isolated from glucosazon, and found to yield 2.9-3.6 p.ct. furfural. Gluconic acid distilled with hydrochloric acid gave traces of furfural; so also with sulphuric acid and manganic oxide.

Starch was oxidised with permanganate, and a mixture of products obtained of which one gave a characteristic violet colouration with phloroglucol, with an absorption-band at the D line. On distilling with HCl furfural was obtained in some quantity. The product in question was found to be very sensitive to the action of bases, and was destroyed by the incidental operation of neutralising the mixture of oxidised products with calcium carbonate. It was found impossible to isolate the compound.

UNTERSUCHUNGEN UEBER DIE PENTOSANBESTIMMUNG MITTELST DER SALZSAeURE-PHLORO-GLUCIN-METHODE.[8]

E. KROeBER (Journ. f. Landwirthschaft, 1901, 357).

INVESTIGATION OF THE HYDROCHLORIC ACID-PHLOROGLUCINOL METHOD OF DETERMINING PENTOSANES.

This paper is the most complete investigation yet published of the now well-known method of precipitating and estimating furfural in acid solution by means of the trihydric phenol. In the last section of the paper is contained the most important result, the proof that the insoluble phloroglucide is formed according to the reaction

C{5}H{4}O{2} + C{6}H{6}O{3} - 2H{2}O = C{11}H{6}O{3},

also, by varying the proportions of the pure reagents interacting, that the condensation takes place invariably according to this equation.

Incidentally the following points were also established:—The solubility of the phloroglucide, under the conditions of finally separating in a condition for drying and weighing, is 1 mgr. per 100 c.c. of total solution, made up of the original acid solution, in which the precipitation takes place, and the wash-water required to purify from the acid. The phloroglucide is hygroscopic, and must be weighed out of contact with the air. The presence of diresorcinol is without influence on the result, provided a sufficient excess of actual phloroglucinol is employed. Thus even with a preparation containing 30 p.ct. of its weight of diresorcinol the influence of the latter is eliminated, provided a weight be taken equal to twice that of the furfural to be precipitated. The phenol must be perfectly dissolved by warming with dilute HCl (1.06 sp.gr.) before adding to the furfural solution. For collecting the precipitate of phloroglucide the author employs the Gooch crucible.

The paper contains a large number of quantitative results in proof of the various points established, and concludes with elaborate tables, giving the equivalents in the known pentoses and their anhydrides for any given weight of phloroglucide from 0.050 to 0.300 grm.

UEBER DEN PENTOSAN-GEHALT VERSCHIEDENER MATERIALIEN.

B. TOLLENS and H. GLAUBITZ (J. fuer Landwirthschaft, 1897, 97).

ON THE PENTOSANE CONSTITUENTS OF FODDER-PLANTS AND MALT.

(p. 171) (a) The authors have re-determined the yield of furfural from a large range of plant-products, using the phloroglucol method. The numbers approximate closely to those obtained by the hydrazone method. The following may be cited as typical:

Substance Furfural p.ct.

Rye (Goettingen) 6.03 Wheat (square head) 4.75 Barley (peacock) 4.33 Oats (Goettingen) 7.72 Maize (American) 3.17 Meadow hay 11.63 Bran (wheat) 13.06 Malt 6.07 Malt-sprouts 8.56 Sugar-beet (exhausted) 14.95

(b) A comparison of wheat with wheat bran, &c. was made by grinding in a mortar and 'bolting' the flour through a fine silk sieve. The results showed:

Furfural p.ct. Original wheat 4.75 Fine flour 1.73 Bran (24 p.ct. of wheat) 11.25 Wheat-bran of commerce 13.06

It is evident that the pentosanes of wheat are localised in the more resistant tissues of the grain.

(c) An investigation of the products obtained in the analytical process for 'crude fibre' gave the following:

(1) In the case of brewers' grains:

100 grms. grains gave furfural = 29.43 pentosane ———————- 20 " crude fibre " = 2.52 Acid extract " = 22.76 Alkali " " = 1.20 Deficiency from total of original grains 2.95 ——-

29.43

(2) In the case of meadow hay:

The crude fibre (30 p.ct.) obtained retained about one fourth (23.63 p.ct.) of the total original pentosanes.

(d) An investigation of barley-malt, malt-extract or wort, and finished beer showed the following: An increase of furfuroids in the process of malting, 100 pts. barley with 7.97 of 'pentosane' yielding 82 of malt with 11.18 p.ct. 'pentosane'; confirming the observations of Cross and Bevan (Ber. 28, 2604). Of the total furfuroids of malt about 1/4 are dissolved in the mashing process. In a fermentation for lager beer it was found that about /10 of the total furfuroids of the malt finally survive in the beer; the yield of furfural being 2.92 p.ct. of the 'total solids' of the beer. In a 'Schlempe' or 'pot ale,' from a distillery using to 1 part malt 4 parts raw grain (rye), yield of furfural was 9 p.ct. of the total solids.

In a general review of the relationships of this group of plant-products it is pointed out that they are largely digested by animals, and probably have an equal 'assimilation' value to starch. They resist alcoholic fermentation, and must consequently be taken into account as constituents of beers and wines.

UEBER DAS VERHALTEN DER PENTOSANE DER SAMEN BEIM KEIMEN.[9]

A. SCHOeNE and B. TOLLENS (Jour. f. Landwirthschaft, 1901, 349).

BEHAVIOUR OF PENTOSANES OF SEEDS IN GERMINATION.

The authors have investigated the germination of barley, wheat, and peas, in absence of light, and generally with exclusion of assimilating activity, to determine whether the oxidation with attendant loss of weight, which is the main chemical feature of the germination proper, affects the pentosanes of the seeds. The following are typical of the quantitative results obtained, which are stated in absolute weights, and not percentages.

Original seed Malt or Pentosane in germinated product A B A B Barley 500.00 434.88 39.58 40.38 " 500.00 442.26 40.52 41.17 Peas 300.00 286.60 15.25 15.97

The authors conclude generally that there is a slight absolute increase in the pentosanes, and that the pentosanes do not belong to those reserve materials which undergo destructive oxidation during germination.

In this they confirm the previously published results of De Chalmot, Cross and Bevan, and Gotze and Pfeiffer.

UEBER DEN GEHALT DER BAUMWOLLE AN PENTOSAN.

H. SURINGAR and B. TOLLENS (Ztschr. angew. Chem., 1897, I).

PENTOSANE CONSTITUENTS OF COTTON.

(p. 290) It has been stated by Link and Voswinkel (Pharm. Centralhalle, 1893, 253), that raw cotton yields 'wood gum' as a product of hydrolysis. The authors were unable to obtain any pentoses as products of acid hydrolysis of raw cotton, and traces only of furfural-yielding carbohydrates. They conclude that raw cotton contains no appreciable quantity of pentosane.

FOOTNOTES:

[8] This paper appears during the printing of the author's original MS.

[9] This paper appears during the printing of the author's original MS.



SECTION VI. THE LIGNOCELLULOSES

(p. 131) Lignocellulose Esters.—By a fuller study of the ester reactions of the normal celluloses we have been able to throw some light on the constitutional problems involved; and we have extended the investigations to the jute fibre as a type of the lignocelluloses, from the results of which we get a clearer idea of the relationships of the constituent groups.

Taking the empirical expression for the complex, i.e. the entire lignocellulose, the formula C{12}H{18}O{9}, we shall be able to compare the ester derivatives with those of the celluloses, which we have also referred to a C{12} unit. But we shall require also to deal with the constituent groups of the complex, which for the purposes of this discussion may be regarded as (a) a cellulose of normal characteristics—cellulose alpha; (b) a cellulose yielding furfural on boiling with condensing acids—cellulose beta; and (c) a much condensed, and in part benzenoid, group which we may continue to term the lignone group.

The latter has been specially examined with regard to its proportion of OH groups, as a necessary preliminary to the investigation of esters, in producing which the entire complex is employed. It will be shown that the ester groups can be actually localised in various ways, as in the main entering the cellulose residues alpha and beta. But that the lignone group takes little part in the reactions may be generally concluded on the evidence of its non-reactivity as an isolated derivative, (1) By chlorination, &c. it is isolated in the form of an amorphous body, but of constant composition, represented by the formula C_{19}H_{18}Cl_{4}O_{9}. This compound, soluble in acetic anhydride, was boiled with it for six hours after adding fused sodium acetate, and the product separated by pouring into water. The dilute acid filtered from the product contained no hydrochloric acid nor by-products of action. The product showed an increase of weight of 7.5 p.ct. For one acetyl per 1 mol. C_{19}H_{18}Cl_{4}O the calculated increase is 8.0 p.ct. It is evident from the nature of the derivative that this result cannot be further verified by the usual analytical methods. (2) The chlorinated derivative is entirely soluble in sodium sulphite solution. This solution, shaken with benzoyl chloride, with addition of sodium hydrate in successive portions, shows only a small formation of insoluble benzoate, which separates as a tarry precipitate. (3) The empirical formula of the lignone complex in its isolated forms indicates that very little hydrolysis occurs in the processes of isolation. Thus the chlorinated product we may assume to be derived from the complex C_{19}H_{22}O_{9}. In the soluble by-products from the bisulphite processes of pulping wood the lignone exists as a sulphonated derivative, C_{24}H_{23}(OCH_{3})_{2}.(SO_{3}H).O_{7}. The original lignone may be regarded as passing into solution as a still condensed complex derived from C_{24}H_{26}O_{12} (Tollens). There is evidently little attendant hydroxylation, and another essential feature is the small molecular proportion of groups showing the typical sulphonation.

It appears that in the lignone the elements are approximately in the relation C_{6} : H_{6} : O_{3}, and it may assist this discussion to formulate the main constitutional types consistent with this ratio, viz.:

(1) The trihydroxybenzenes C_{6}H_{3}(OH)_{3}.

(2) Methylhydroxyfurfural C_{5}H_{2}O.(OH)(CH_{3}).

(CH_{3}) / (3) Methylhydroxypyrone CO<C_{4}H_{2} O / (OH)

___ (4) Trioxycyclohexane CH CH CH CH CH CH / / / O O O

It is probable that all these types of condensation are represented in the lignone molecules, since the derivatives yielded in decompositions of more or less regulated character are either directly derived from or related to such groups. For the moment we pass over all but the general fact of complexity and the marked paucity of OH-groups. It would be of importance to be able to formulate the exact mode of union of the lignone with the cellulose residues to constitute the lignocellulose. The evidence, however, does not carry us farther than the probability of union by complicated groups and of large dimensions; for not only is the lignone isolated in condensed and non-hydroxylated forms, but the cellulose also is not hydrated or hydrolysed further than in the ratio 3C{6}H{10}O{5}.H{2}O. It is probable, therefore, that the water combining with the residues at the moment of their resolution is relatively small.

Lastly, we have to remember, when dealing with the statistical results of the reactions to be described, that the approximate proportions per cent. of the constituent groups are:

Cellulose alpha 65 " beta 15 = 100 lignocellulose. Lignone 20

Jute Benzoates.—In preparing the jute for treatment it was boiled in alkaline solution (1 per cent. NaOH), washed with water and dilute acid, again washed, dried, and weighed.

In the ester reaction the reagents were employed in the proportion C_{12}H_{18}O_{9} : 3NaOH : 2C_{6}H_{5}COCl. A series of quantitative experiments gave yields of 126-130 p.ct. of benzoate [calculated for monobenzoate 134 p.ct.].

The results were confirmed by ultimate analysis. The monobenzoate therefore represents a maximum, and this molecular proportion is one-half of that observed with the normal cellulose, calculated to the same unit.

Localisation of Benzoyl Group.—The entrance of the ester group affects the typical colour reactions of the lignocellulose, which are fainter. The ferric ferricyanide reaction almost disappears. The lignone group is unaffected, and combines with chlorine as in the original. The lignone chloride is removed by sodium sulphite solution, and the residue is a cellulose benzoate. The loss of weight due to the elimination of the lignone was 12.7 p.ct. Calculating per 100 of the original lignocellulose this becomes 16. These statistics further confirm the localisation of the benzoyl group in the cellulose residue. It is to be noted that the presence of the benzoyl group renders the cellulose more resistant to hydrolytic actions. Thus, to bring out this fact more prominently, we may calculate the yield of residual cellulose benzoate p.ct. of original jute, and we find it 109 p.ct. Taking a maximum proportion for original cellulose—viz. 85—this benzoate represents a yield of 129 p.ct., as against the theoretical for a monobenzoate, 132 p.ct.

Furfural Numbers.—The percentage of furfural obtained by boiling with HCl of 1.06 sp.gr. was 3.02 and 3.29 in separate determinations. Calculating to the original lignocellulose, the percentage, 4.21, indicates a considerable loss of the furfural-yielding constituent. The effect was also apparent in the cellulose (benzoate) isolated by chlorination &c., the percentage being 1.39 p.ct., and calculated to the original jute benzoate 1.59 p.ct. Under the conditions adopted in dissolving away the chlorinated lignone the original non-benzoated lignocellulose would have yielded a cellulose giving 6 to 7 p.ct. furfural.

Since the benzoyl group is hardly calculated to produce a constitutional change affecting the furfural constants, it was necessary to examine the effect of the preliminary alkaline treatment, and the change in the furfuroid group was in fact localised in this reaction. It was found that, on washing the alkali from the mercerised jute, and further purifying the residue, this latter yielded only 4.2 p.ct. furfural [3.4 p.ct. on original fibre]. The alkaline solution and washings were acidified and distilled from 10 p.ct. HCl, yielding an additional 3.6 p.ct. calculated to the original lignocellulose. By treatment with the concentrated alkali, therefore, the furfuroid of the original lignocellulose undergoes little change, but is selectively dissolved. This point is under further investigation.

(p. 132) Acetylation of Lignocelluloses.—Acetates are readily formed by boiling the lignocelluloses with acetic anhydride. The derivatives obtained from jute are only generally mentioned in the 1st edition (p. 132). A further study of the reactions in regard to special points has led to some more definite results. The yields of product by the ordinary and simple process are 114-115 p.ct. But on analysing the product an important discrepancy is revealed.

For the saponification we employ a solution of sodium ethylate in the cold. The following numbers were obtained:

Acetic acid Hydrocellulose residue 27.2 77.8 Calc. for diacetate on C_{12}H_{18}O_{9} 30.8 78.4

The derivative is approximately a diacetate, and on the assumption of a simple ester reaction the yield should be 127 p.ct. Assuming that the difference of 13 p.ct. is due to loss of water by internal condensation, it appears that for each acetyl group entering, 2 mol. H_{2}O are split off.

The jute acetate showed the normal reaction with chlorine, and the lignone chloride was dissolved by treatment with sodium sulphite solution. The fibrous residue was colourless. It proved to be a cellulose acetate. The following numbers were obtained on saponification:

Acetic acid Cellulose 31.6 70.0 30.9 68.8 Calc. for diacetate on C_{12}H_{20}O_{10} 29.4 79.9

The interpretation of these numbers appears to be this: in the original reaction with the lignocellulose it is the cellulose residue which is acetylated, and at the same time condensed. The cellulose residue which undergoes condensation is not of the normal constitution, since the normal cellulose is acetylated without condensation (see p. 41). On saponification a portion of the cellulose, in again combining with water, is hydrolysed to soluble products. The lignone group as it exists in the lignocellulose has no free OH groups, and probably no free aldehydic groups such as would react with the anhydride. Such groups may, however, be originally present, and may take part in the internal condensations which have been shown to occur. The furfural constants of the lignocellulose are unaffected by the acetylation and condensation. The hygroscopic moisture of the product is lowered from 10-11 p.ct. in the original to 4.5 p.ct. The ferric ferricyanide reaction is inhibited by the disappearance of the reactive groups, upon which this curious and characteristic phenomenon depends (1st ed.).

Acetylation of Benzoates.—The cellulose dibenzoate (C_{12} basis) and the jute monobenzoate were acetylated under comparative conditions The results were as follows:

C_{12} basis Cellulose dibenzoate Jute monobenzoate Calc. for Calc. for Found diacetate on Found diacetate on Ester reaction dibenzoate monobenzoate Yield 111 p.ct. 115 p.ct. 124 p.ct. 120 p.ct.

Saponification {Cellulose} {Lignocellulose} 53.5 52.6 59.8 61.9 NaOH combining 21.3 23.9 28.4 24.3

From these results it would appear that the number of acetyl groups entering the benzoates is the same as with the unbenzoylated fibres, the benzoyl has no influence upon the hydroxyls as against the acetyl. At the same time the internal condensation noticed in the acetylation of the jute appears not to occur in the case of the benzoate.

Nitric Esters.—The numbers resulting from the quantitative study of the ester reaction and product (1st ed. p. 133) show a very large divergence of the yield of product from that which would be calculated from its composition (N p.ct.) on the assumption that the ester reaction is simple. We have repeated the results, and find with a yield of 145 p.ct. that the product contains 11.8 p.ct. N.

The reaction

C_{12}H_{18}O_{9} + 4HNO_{3} - 4H_{2}O

gives a tetranitrate with 11.5 p.ct. N and a yield of 159 p.ct. The ester reaction, therefore, is not simple. There are two sources of the loss of weight. The first of these is evident from the occurrence of certain secondary reactions which result in the solution of a certain proportion of the fibre substance in the acid mixture. To determine this quantitatively we have devised a suitable variation of the method of combustion with chromic acid (1st ed.).

The variation is required to meet the difficulty occasioned by the tension of the nitric acid and products of deoxidation. The mixed acids (10 c.c.), containing the organic by-products in solution, are carefully diluted in a small flask with an equal volume of water, preventing rise of temperature. Nitrous fumes are evolved during the dilution. Strong sulphuric acid (15 c.c.) is now added, and the residue of nitrous fumes expelled by a current of air, agitating the contents of the flask from time to time. The combustion with CrO_{3} is then proceeded with in the ordinary way. The gases evolved are measured (total volume) and calculated to C present in the form of products derived from the lignocellulose; and, assuming that this contains 47 p.ct. C, we may express the result approximately in terms of the fibre substance. The method was controlled by blank experiments, in which citric acid was taken as a convenient carbon compound for combustion. The C found was 34.9 p.ct. as against 34.3 p.ct. calculated. By this method we find that with maximum yields of nitrate at 143-145 p.ct. the organic matter in solution in the acid mixture amounted to 4.9 to 5.3 p.ct. of the original lignocellulose.

Introducing this quantity as a correction of the yield of nitrate in the original reaction, we must express the 143 parts as obtained from 95 of fibre substance instead of 100.

The yield per molecule C{12}H{18}O{9} (= 306) is therefore 462, whereas for a tetranitrate formed by a simple ester reaction the yield should be 486. The difference (24) represents 1.5 mol. H{2}O split off by internal condensation.

The correction for total N is relatively small, raising it from 11.5 to 12.2, which remains in close agreement with the experimental numbers.

Monobenzoate.—Treated with the acid mixture yields a mixed nitrate. The yield is 130 p.ct., and the product contains 7.6 p.ct. O.NO{2} nitrogen. These numbers approximate to those required for reaction with 4HNO{3} groups, three of the residues entering the cellulose, and one (as NO{2}) the benzene ring of the substituting group. For such a reaction the calculated numbers are: Yield 144 p.ct.; O.NO{2} nitrogen 7.1 p.ct.

The experimental numbers require correcting for the amount of loss in the form of products soluble in the acid mixture, viz. 7.6 p.ct.; but they remain within the range of the experimental errors sufficiently to show that the benzoyl group limits the number of OH groups taking part in the ester reaction to three. The corrected yield per 1 mol. of jute benzoate (410) is 576, as against the calculated 590 for 4HNO{3} reacting. A loss of 1H{2}O per molecule by internal condensation is therefore indicated.

Denitration.—The removal of the nitric groups from the esters is effected by digestion with ammonium sulphide. But the reactions are by no means simple. There is considerable hydrolysis of the lignocellulose to soluble products. Thus the tetranitrate yields only 46.4 of denitrated fibre in place of the calculated 66. The product is a cellulose, yielding only 0.5 per cent. furfural. The hydrolysed by-products, moreover, when freed from sulphur and distilled from hydrochloric acid, yielded only an additional 2.5 p.ct. furfural, calculated to the original lignocellulose.

These statistics confirm the evidence that the ester reaction is not simple. Such changes take place in the lignone-beta-cellulose complex that they revert, not to their original form, but to soluble derivatives of different constitution. The mixed nitrate from the benzoate is denitrated to a cellulose amidobenzoate, which confirms the localisation of a nitro-group in the benzoyl residue.

(p. 157) General Characteristics of the Lignocelluloses.—Later investigations have somewhat modified and simplified our views of the constitution of the typical lignocellulose (jute), so far as this can be dealt with by the statistics of its more important decompositions (original, pp. 157-161).

Cellulose.—There is little doubt that the furfural-yielding groups of the original are isolated in the form of the beta-cellulose. Tollens emphasises this fact in his studies of cellulose-estimation methods. We had previously shown (original, p. 159) that the yield of furfural is not affected by the chlorination, but it appears from our numbers that only 50 p.ct. of these groups remain in the isolated cellulose, the residue undergoing hydrolysis to soluble compounds. In a carefully regulated hydrolysis following the chlorination it appears that the furfuroids are almost entirely conserved in the form of a cellulose.

Moreover, an investigation of the products dissolved by sodium sulphite solution from the chlorinated fibre has shown that they are practically free from furfuroids. This enables us to exclude the furfural-yielding groups from the lignone complex. At the same time, through our later studies of the hydroxyfurfurals, it is certain that these products are represented in the fibre substance and probably in the lignone complex.

Chlorination Statistics.—It has been pointed out by a correspondent—to whom we express our indebtedness—that we have made a mistake in calculating the proportion of lignone from the ratio of the Cl combining with the fibre substance or lignocellulose (p.ct), to that of the Cl present in the isolated lignone chloride (p.ct.). The lignocellulose combines with chlorine in the ratio 100 : 8, but the lignone chloride containing 26.7 of chlorine means that, neglecting the hydrogen substituted, 73 of lignone combine with the 27 of chlorine approximately. On the uniform percentage basis the calculated proportion of lignone would be 8/37, or a little over 20 p.ct.

In regard to the proportion of hydration attending the resolution, we have shown on constitutional grounds that this must be relatively small. Assuming approximately the formula C_{19}H_{22}O_{9} for the lignone residue as it exists in combination, and the anhydride formula for the cellulose, these revised statistics now appear, as regards the carbon contents of the lignocellulose:

Cellulose, 44.4 C; lignone, 57.8. 80 x 44.4 / 100 = 35.52 20 x 57.8 / 100 = 11.56

47.08 p.ct. C in lignocellulose.

These conclusions are in accordance with the experimental facts, and, taken together with the new evidence we have accumulated from a study of the lignocellulose esters, we may sum up the constitutional points as follows: The lignocellulose is a complex of

Cellulose alpha Cellulose beta Lignone 65 p.ct. 15 p.ct. 20 Allied to the normal Yielding furfural One-third of which celluloses approximately 50 p.ct. is of benzenoid type

The lignone contains but little hydroxyl. The celluloses are in condensed hydroxyl union with the lignone, but the combination occurs by complexes of relatively large molecular weight.

DIE CHEMIE DER LIGNOCELLULOSEN—EIN NEUER TYPUS.

W. C. HANCOCK and O. W. DAHL (Berl. Ber., 1895, 1558).

Chemistry of Lignocelluloses—A New Type.

The stem of the aquatic AEschynomene aspera offers an exceptional instance of structural modification to serve the special function of a 'float,' 1 grm. of substance occupying an apparent volume of 40-50 c.c. This pith-like substance is morphologically a true wood (De Bary), and the author's investigations now establish that it is in all fundamental points of chemical composition a lignocellulose, although from its colour reactions it has been considered by botanists to be a cellulose tissue containing a proportion of lignified cells. Thus the main tissue is stained blue by iodine in presence of hydriodic acid (1.5 s.g.), and the colour is not changed on washing. The ordinary lignocelluloses are stained a purple brown changed to brown on washing. The reactions with phloroglucol and with aniline salts, characteristic of these compounds, is only faintly marked in the main tissue, though strongly in certain individual cells.

The following quantitative determinations, however, establish the close similarity of the product to the typical lignocelluloses:

Elementary Analysis.—C 46.55, H 6.7. Furfural 11.6 p.ct., of which there remained in the residue from alkaline hydrolysis (71 p.ct.) 8.0, i.e. about 70 p.ct. The distribution of the furfuroids is therefore not affected by the alkaline treatment.

Chlorination.—The substance (after alkaline hydrolysis) takes up 16.9 p.ct. Cl, of which approximately one-half is converted into hydrochloric acid.

_Methoxyl._—O.CH_{3} estimated = 2.9 p.ct.

Ferric Ferricyanide Reaction.—Increase of weight due to blue cyanide fixed (1) 75 p.ct., (2) 96 p.ct. Ratio, Fe : CN = 1 : 2, 4.

Hydroxyl Reactions.—In the formation of nitric esters and in the sulphocarbonate reaction the substance gave results similar to those obtaining for the jute fibre.

These results establish the general identity of this peculiar product of plant life with the lignocelluloses, at the same time that they show that certain of the colour reactions supposed to characterise the lignocelluloses are due to by-products which may or may not be present.

(p. 172) Composition of Elder Pith.—In a systematic investigation of the celluloses in relation to function we shall have to give special attention to the parenchymatous tissues of all kinds. These are, for structural reasons, not easily isolated, for which reason and their generally 'inferior' functions they do not present themselves to chemical observation in the same obvious way as do their fibrous relatives. The pith of the elder, however, is readily obtained in convenient masses, and a preliminary investigation of the entire tissue has established the following points:

The reactions of the tissue are in all respects those of the lignocelluloses.

Composition.—Ash, 2.2 p.ct.; moisture in air-dry state, 12.3 p.ct. Alkaline hydrolysis (loss): (a) 14.77, (b) 17.84. Cellulose (yield), 52.33 p.ct. Nitrate-reaction complicated by secondary reactions and yields low, 90.95 p.ct. Sulphocarbonate reaction: Resists the treatment, less than 10 p.ct. passes into solution.

Furfural.—The original tissue yields 7.13 p.ct.; the residue from alkaline hydrolysis (b) 5.40 p.ct.

This tissue is, therefore, a lignocellulose having the chemical characteristics typical of the group, but of less resistance to hydrolytic actions.

The investigation will be prosecuted in reference to the cause of differentiation in this latter respect. Probably the pectocelluloses are represented in the tissue.

The Insoluble Carbohydrates of Wheat (grain).

H. C. SHERMAN (J. Amer. Chem. Soc., 1897, 291).

(p. 171) This is a study of the constituents of the cell-walls of wheat grain. Bran was taken as the most convenient form of the raw material, being freed from starch by treatment with malt extract, and further treated (1) with cold dilute ammonia, (2) cold dilute soda lye (2 p.ct. NaOH), and (3) boiling 0.1 p.ct. NaOH. The product retained only 1.25 p.ct. proteids, and yielded 15.62 p.ct. furfural.

Acid Hydrolysis.—The product was boiled 30 mins. with dilute acid (1.25 p.ct. H{2}SO{4}), and the solution boiled until the Fehling test showed no further increase of monoses. At the limit the reducing power of the dissolved carbohydrates was 91.3 p.ct., that of dextrose. Converted into osazones the analysis showed them to be pure pentosazones. The hemicellulose of wheat is, therefore, according to the author, pure pentosane.

Residue.—This was a lignocellulose yielding 11.5 p.ct. furfural. It was subjected to a series of treatments with ferric ferricyanide, and the proportion of Prussian blue fixed was determined by increase of weight, viz. from 10 p.ct. to 47 p.ct. according to the conditions. The results confirmed those of Cross and Bevan first obtained with the typical lignocellulose (jute).

Chlorination.-The residue was boiled with dilute alkali, washed, and exposed to chlorine gas. The resulting lignone chloride was isolated by solution in alcohol, &c. It yielded 26.7 p.ct. Cl on analysis. In this and its properties it appeared to be identical with the product isolated by Cross and Bevan from jute, with the empirical formula C{19}H{18}Cl{4}O{9}.

Cellulose was isolated from the residue by three of the well-known methods, and the following comparative numbers are noteworthy:

_____________ F. Schulze Lange Cross and Method Dil. HNO_{3} Fusion KOH Bevan KClO_{3} Chlorine, &c. ______ ___ __ ___ Cellulose p.ct. obtained 66.0 39.3-43.1 66.5 Furfural p.ct. of cellulose 7.0 3.96 5.62 Residual nitrogen 0.22 0.03 0.00 Ferricyanide reaction, Prussian blue fixed 6.04 0.89 0.92 ______ ___ __ ___

The author remarks: 'It is evident no one feature can be urged as a criterion in judging between the methods, but all must be taken into consideration. Such a comparison shows the superiority of the chlorination method.'

The cellulose is not of the normal (cotton) type, since on treatment with sulphuric acid it dissolves with considerable discolouration, but only to the extent of about 80 per cent. The dissolved monoses converted into osazones were found to consist of hexoses only. The cellulose treated with caustic soda solution (5 p.ct. NaOH) in the cold yielded 20 p.ct. of its weight of soluble constituents, but as the residue yielded 3.34 p.ct. furfural the attack of the alkali is by no means confined to the furfuroids.

Animal Digestion of the Constituents of Bran.—Observations on a steer fed upon wheat bran only established the following percentage digestion of the several constituents:

Soluble carbohydrates 96.9 Starch 100.0 Free pentosanes 60.2 Cellulose 24.8 Lignin complex 36.7 Proteid 82.96 Ether extract 42.73 ____ _

Nitrogen-free extract 76.08 Crude fibre 32.21

JOURNAL OF THE IMPERIAL INSTITUTE

(Research Department, Vols. 1-2, 1895-6).

(p. 109) In this journal appear a series of notices of the results of analyses of vegetable fibres by the method described in 'Report on Miscellaneous Fibres' (Col. Ind. Exhibition Reports, p. 368) [C. F. Cross]. These investigations deal with the following subjects:

1895. p. 29 Various Indian Fibres—more particularly Sida. 118 (a) Fibres from Victoria; (b) Special Analyses of (a) Samples of Jute; (c) Paper-making Fibres from S. Australia. 202 Fibres from Victoria. 287 Fibres from Victoria. 366 Sisal from Trinidad. 373 Rope-fibres from Grenada. (b) 398 Report of Experiments on Indian Jute (1). 435} Fifth and Sixth Report on Australian Fibres. 473} 1896. 68 Hibiscus and Abroma Fibres. 104-5 Hibiscus, Urena, and Crotalaria Fibres. 141 Indian Sisal (c) 182-3 Report of Experiments on Indian Jute (2). 264 Sanseviera from Assam.

From the above we may draw the general conclusion that the scheme of investigation has been found in practice to answer its main purpose, viz. to afford such numerical constants as determine industrial values. In illustration we may cite (a) the results of analyses of specially selected samples of jute, from which it will be seen that there is a close concordance of value as ordinarily determined from external appearance, with the chemical constants as determined in the laboratory.

___________ Quality of Jute _____ _______ Low Medium Extra Extra Fine _____ __ __ __ __ Moisture 11.0 10.4 11.1 9.6 Ash 0.87 2.8 1.0 0.7 Alkaline hydrolysis (a) 5 mins. boiling 13.2 11.6 8.5 9.1 Alkaline hydrolysis (b) 60 mins. boiling 16.1 17.5 12.5 13.1 Mercerising treatment 9.2 10.5 10.3 8.5 Nitration (increase p.ct.) 36.6 35.7 37.5 36.7 Cellulose (yield) 71.4 70.0 79.0 77.7 Acid purification 2.6 1.3 1.9 2.0 _____ __ __ __ __

A useful series of experiments, initiated by the Institute, is that noted under (b) and (c) above.

(1) To ascertain the quality of the fibre extracted from the plant at different stages of growth, quantities of 400 lbs. of the stalks were cut at successive stages and the fibre isolated after steeping 14-20 days. The fibre was shipped to England and chemically investigated, with the following results:

No. 1. Cut before appearance of inflorescence. " 2. " after budding. " 3. " in flower. " 4. " after appearance of seed-pod. " 5. " when fully matured.

(1) (2) (3) (4) (5) Moisture 11.55 8.74 10.7 10.0 9.72 Ash 1.1 1.1 1.1 1.1 0.90 Alkaline hydrolysis (a) 6.2 8.5 9.7 8.9 7.3 " " (b) 10.5 11.9 11.6 12.0 11.2 Mercerising treatment 10.2 10.7 12.0 8.1 11.0 Nitration 37.2 32.1 32.2 33.2 36.6 Cellulose 74.0 76.2 74.1 74.8 76.4 Acid purification 0.8 0.5 0.7 2.4 1.4

It will be thus seen that there are no changes of any essential kind in the chemical composition of the bast fibre throughout the life-history of the plant, confirming the conclusion that the 'incrustation' view of lignification is consistent only with the structural features of the changes, and so far as it has assumed the gradual overlaying of a cellulose fibre with the lignone substance it is not in accordance with the facts.

Examination of the samples from the point of view of textile quality showed a superiority of No. 1 in fineness, softness, and strength; from this stage there is observed a progressive deterioration, but the No. 4 sample (which was taken at the usual period of cutting) is superior to No. 5.

In a further series of experiments (c) the jute was subjected to certain chemical treatments immediately after the separation of the fibre from the plant. These consisted in steeping (1) in solution of sodium carbonate, as well as of plant ashes, and (2) in sulphite of soda, the purpose of the treatments being to modify or arrest the changes which take place in the fibre when press-packed in bales for shipment. The samples were shipped from India under the usual conditions and examined soon after arrival. It was found that the chemical treatments had produced but small changes in chemical composition of the fibre-substance. The sulphite treatment was the more marked in influence, somewhat lowering the cellulose and nitration constants. The conclusion drawn from the results was that they afford no prospect of any useful modification, i.e. improvement of the textile quality of the fibre by any chemical treatments such as could be applied to the fibre on the spot before drying for press-packing and shipment.

The other matters investigated in the Institute laboratory and reported on as indicated above are rather of commercial significance, and contributed no points of moment to the chemistry of cellulose.

OBSERVATIONS ON SOME OF THE CHEMICAL SUBSTANCES IN THE TRUNKS OF TREES.

F. H. STORER (Bull. Bussey Inst., 1897, 386).

(p. 172) An examination of the outer and inner wood and of the bark of the grey birch, at different seasons of the year, gave the following yields of furfural p.ct. on the dry substance:

______ Wood ___ Bark Inner Outer __ __ __ _ May 21.3 19.6 16.7 July 16.6 18.8 11.4 October 16.2 16.3 12.3 __ __ __ _

The paper contains the results of treating the woods and various vegetable products with hydrolysing agents in order of intensity: (a) Malt-extract at 60 deg.C., (b) boiling dilute HCl (1.0 p.ct. HCl), and (c) boiling dilute HCl (2.5 p.ct.). The residues were found to yield considerable proportions of furfural. The following numbers are typical:

Birch Stones of Bark Wood Date Apricot Peach Action of malt extract calcu- lated as starch dissolved 4.24 3.5 5.2 1.5 Residue boiled, 1 p.ct. HCl Mannan gave pentosanes dissolved. 11.7 14.1 6.7 Residue yielded furfural 19.3 17.8 3.4 9.6 9.7

The proportion of pentosanes (furfuroids) removed, i.e. hydrolysed by boiling with hydrochloric acid of 2.5 p.ct. HCl, is shown by the following estimations of furfural:

Birch Sugar maple Apricot stones Bark Wood Outer Inner wood wood In original substance 16.7 19.6 18.2 20.7 18.4 In residue from action 6.53 8.6 4.9 6.4 7.0 of 2.5 p.ct. HCl

Wood Gum.—The paper contains some observations on the various methods of isolating this product. Attention is directed to the necessary impurity of the product, and to the fact that the numbers for furfural and for the xylose yielded by hydrolysis are considerably less than for a pure pentosane.

Estimation of Cellulose.—The author investigated the process of Lange and the 'celluloses' obtained from various raw materials. The products from the woods of birch and maple contained furfural-yielding constituents, represented by yields of 6-8 p.ct. furfural. Preference is given to the process by comparison with others, at the same time that it is recommended in all cases to examine the product for furfural quantitatively, converting the numbers into pentosane equivalents, and subtracting from the total 'cellulose' to give the true cellulose.

ZUR KENNTNISS DER MUTTERSUBSTANZEN DES HOLZGUMMI.

E. WINTERSTEIN (Ztschr. Physiol. Chem., 1892, 381).

ON THE MOTHER SUBSTANCES OF WOOD-GUM.

(p. 188) According to the text-books beech-wood may be regarded as the typical raw material for the preparation of the laboratory product known as wood-gum. The author has subjected beech-wood and beech-wood cellulose (Schulze process) to a range of hydrolytic treatments, acid and alkaline, in order to determine the conditions of selective action upon the mother substance of the wood-gum. In the main it appears that this group of furfuroids is equally resistant with the cellulose constituents of the wood; in fact, that the mother substance of wood-gum is a modified cellulose, and exists in the wood in chemical combination with the 'incrusting substances.'

Of the author's experimental results the following may be cited as typical:

Yield of furfural Substance p.ct. Original beech-wood 13.8

After boiling 3 hrs. with 1.25 p.ct. H{2}SO{4} (residue) 10.1

" " " " 5.0 " " " 5.6

Cellulose—isolated by Schulze process (yield 53 p.ct.) 6.9

" after further 14 days' digestion with the Schulze acid (HNO{3} + KClO{3}) 5.9

" after extraction with 5 p.ct. NaOH in cold (residue) 5.0

" after second extraction with 5 p.ct. NaOH in cold (residue) 4.4

UEBER DIE FRAGE NACH DEM URSPRUNG UNGESAeTTIGER VERBINDUNGEN IN DER PFLANZE.

C. F. CROSS, E. J. BEVAN, and C. SMITH (Berl. Ber., 1895, 1940).

ON THE SOURCE OF THE UNSATURATED COMPOUNDS OF THE PLANT.

(p. 179) In distilling for furfural by the usual methods of boiling cellulosic products with condensing acids, the furfural is accompanied by volatile acids, also products of decomposition of the cellulosic complex. A series of distillations was carried out with dilute sulphuric acids of varying concentration from 10-50 H_{2}SO_{4} : 90-50 H_{2}O by weight, using barley straw as a typical cellulosic material. The distillates were collected in successive fractions, and the furfural and volatile acid determined. The results are given in the form of curves. The aggregate yields were as follows:—

Concentration of acid (H{2}SO{4}) p.ct. 10 15 20 30 40 50

Furfural yield p.ct. of straw 2.0 2.0 4.4 10.1 11.5 11.0

Volatile acid (calculated as acetic acid) p.ct. of straw 1.7 1.9 3.1 4.3 6.3 14.8

With acids up to 20 p.ct. H{2}SO{4} both products are formed concurrently and in nearly equal quantity. With the 30 p.ct. acid there is a great increase in the total furfural, and with the 40 p.ct. acid it reaches nearly the maximum obtainable with HCl of 1.06 s.g. (Tollens), in this case 12.4 p.ct. The volatile acid increases, but in less ratio; it is also produced concurrently. With 50 p.ct. H{2}SO{4} the conditions are changed. The total furfural is rapidly formed, whereas the volatile acid continues to be formed long after the aldehyde ceases to come over. Moreover, whereas in the previous cases it was mainly acetic acid, it is now mainly formic acid. The method was then extended to a typical series of celluloses, heated with the more concentrated acid (40-50 p.ct. H{2}SO{4}), with the following results:

_________ Volatile acid ____ Acetic Formic ____ __ __ __ Swedish filter-paper 0.3 2.7 17.2 Esparto cellulose 12.4 3.2 16.6 Bleached cotton trace 3.1 13.2 Raw cotton (American) 5.0 9.4 Jute cellulose 5.2 4.9 22.7 Beech (wood) cellulose 6.4 3.5 14.6 ____ __ __ __

The tendency in the hexoses and their polyanhydrides to split off one carbon atom in the oxidised form, throws some light on the furfurane type of condensation, which is represented in the lignocelluloses. We are still without any evidence as to the possible transition of the hexoses to benzenoid compounds. Such transitions would be more easily explained on the assumption that the celluloses are composed in part of polyanhydrides of the ketoses.