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Proceedings of the Chemical Society, Vol. 8, No. 107 |
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Proceedings of the Chemical Society, London,
Volume 8,
Issue 107,
1892,
Page 29-36
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摘要:
P -R0C E E D I N G S OB THE CHEMICAL SOCIETY. No. 107. Session 1891-9 2. February Mth, 1892. Professor W. A.Tilden, F.R.S., Vice-president, in the Chair. It was announced that the following changes in the Council were proposed by the Council :-As Vice-Presidents : Ah. A. Vernon Hai’court, F.R.S., and Pro- fessor w. Ramsay, F.R.S., vice Professors G. Carey Foster, F.R.S., and J. Emerson Reynolds, M.D., F.R.S. As ordinary inembers of Council: Professor Harold Dixon and Messrs. R.. J. Friswell, John Heron and llT.P. Wynne, vice Dr. E. Atkicson, Professor E. Kinch, Mr. Boverton Redwood and Professor Thomas Purdie. Messrs. Holland Crompton, Bernard Dyer and T. S. Dymond were appointed to audit the Society’s accounts. Certificates were read for the first time in favour of Messrs.Alexander Barrat,t, Bronhenlog, Mostyn. N. Wales ; Frank Comyns, B.A.,55, South Street, Durham ; Joseph Davits, 28, Robarts Road, Anfield, near Liverpool ; James C. Frazer, Victoria Square, Adelaide, South Australia ; John Theodore Hewitt, St. John’s College, Cam-bridge ; William James McKerrow, care of Hall, McKerrow & Co., Nicholas Street, Manchester ; George Harry Major, Coldstream Street, Llanelly ; Reginald Edensor Stanley Richardson, Elmfield, Knighton, Leicester ; Thomas Shortridge Tweedie, The Moat, Annan ; George Isaac James Wells, F.I.C., Kinderton Lodge, lfiddlewick, Cheshire. The following were duly elected Fellows of t’he Society :-Arthur Adams ; Frederick Edward Adams ; Frederick Fielding Bold ; 30 William John Atkinson Butterfield ; Hugh Brown Collins, B.Sc., C.E.; Francis V. Darbishire ; Robert Brooke Floris ; Alfred Thomas Gailleton ; William Percy Hatton ; James Hendrick ; John C. Hew-lett ; Lionel Manfred Jones ; Albert Henry Luckett ; William Cossar Mackenzie ; John Edward Whitley McFall ; Charles Stephen Meacham ; James Hill Mi11ar ; Robert Ludwig Mond ; William Shields Myers ; William Pullinger ; Ernest John Parry ; Charles Frederick Seymour Rothwell ; Thomas John Buckler Sandercock ; James Alexander Schofield ; Thomas Skurray ; George P. Darnell Smith ; Henry John Spray ; Alfred James Squires ; James Sykes ; JIorris William Trewers ; Hugh Woods. The following papers were read :-108. "A search for a cellulose-dissolving (cytohydrolytic) enzyme in the digestive tract of certain grain-feeding animals." By Homce T.Brown, F.ILE.S. The author, in a recent paper by himself and G.H. Morris (C.S. Trans., 1890, 459), has shown that during germination of the seeds of the grasses the cell-membrane of the endosperm is broken dowii and destroyed by a specific cellulose-dissolving enzyme, or cylo-hydrdyst; and that the breaking down of the cell-wall is a necessary preliminary to the dissolution of the reserve starch and proteids of the cell-contents, which otherwise mould not readily come under $he influence of the extremely indiffusible starch and proteid-dissolving enzymes secreted by a certain layer of cells in the embryo. As it was found by the author that the analogous starch-hydrolysing enzyme of animal saliva and of the pancreatic secretion experiences the same diEculty in traversing the tbin cell-membrane, it appeared almost certain that in grain-feeding animals there must be some provision in their economy for removing, during the processes o€ digestion, the inverting cell-membrane of the starch.containing cells of the interior of the grain, zmd of thus bringing the cell-contents fully under the influence of the digestive enzymes of the alimentary canal. An examination of the contents of the small intestine of a pig, fed R few hours before death with barley-meal, conclusively showed that by the time the food had reached this point the originally intact parenchymatous cell-walls of the grain had undergone almost com-plete dissolution, and that the starchy and proteid cell-contents had been completely freed from their cell-envelopes and were being rapidly dissolved under the influence of the pancreatic secretion.As the phenomena were in the highest degree suggestive of the cell-wall being dissolved by an enzynie, the search for this cytohydro- lyst was commenced by a very full examination of the pancreas, that of thepig, horse, ox and sheep being employed, but not the slightest evidence could be obtaiiied that this organ is capable of secreting an enzyme having any action on cellulose. A continuance of the search in the small intestine itself, which is known to possess certain hydrolysing functions, was rendered un-necessary when it was discovered that the action on the cell-wall of the grain food has already taken place before the stomach-contents have passed into the small intestine.It was, therefore, in the stomach itself, or in the salivary glands, that t'he search had to be continued ; but the enquiry was further narrowed by the fact that aiiimal saliva was found to be incapable of exercising any action on cellulose. The experiments on the stomach-membrane and stomach-contents were all made on the horse and the pig. The dissolution of the vege- table cell-membrane in the stomach may be due to one or more of the following causes, viz. :-(1.) To mechanical disint'egration brought about by the " churn-ing '' and " propulsive " movements of the stomach during digestion. (2.) To the action of thc natural acids of the stomacli, which may bring about the dissolution of the cellulose either (u)by direct hydro- lysis, or (b) by converting a zymogen of the grain into an active cytohydrolyst.(3.) To the action of a special enzyme secreted by some portion of the mucous membrane of the stomach. (4.) To the direct or indirect action of living micro-o~ganisms.These may break down the cell-wall by :-(a)A direct attack of the living organism without the intervention of a secreted enzyme. (b.) A previous secretion by the organism of a special cytobydro- lyst. (c.) An indirect production of a cytohydrolyst by the modification of some OE the constituents of the grain by the vital processes of the micro-organisms.(5.) To the self-digestion of the food under the influence of a cyto- hyclrolyst pre-existent in the grain before ingestion. Each one of these possible cases had to be examined separately in order to determine the Vera causa for the destruction of the paren- chymatous cell-wall which undoubtedly takes place in the stomach during digestion. It is shown by numerous experiments that the destruction of the rnembi*ane is not due to mechanical disintegration nor yet to any achion of the stomach-acids, nor is it attributable to the direct or indirect influence of micro-organisms. The cell-mall is, 32 undoubtedly, dissolved by a cytohydrolytic euxyiiie ; but, contra1.y to what' was expected, this enzyiiie is iiot seciaeted by any portion of tlle mucous membrane of the stomach, but is ire-existent in the graiii before ingestion, the animal itself contributing nothing to the result except by affording suitable conditions of temperature, &c., for the action of the enzyme. In a previous paper by the author and G.H. Morris (Zoc. cit.) it was stated that the cellulose-dissolving enzyme which is of so much indirect importance to the plantlet during the germination of the seeds of the grasses is not pre-existent in the seed during its resting stage, but is a, product of the germinative processes. Although this is strictly true as regards the morphologically perfect and highly-matured barley which was used during the greater part of that re- search, it is not strictly true of all barley or grasses, especially of barley growii in this country under somewhat imperfect climatic con-ditions.This, as a rule, contains, even in its resting st:ite, more or less of the cellulose-dissolving enzyme, and the same is true as regards rye. In oats the cytohydrolyst is particularly abandant, and this fact explains the very great rapidity with which the endo- sperm of the oat is disintegrated in the early stages of digestion in the horse as observed by the author, and also throws considerable light on the cause of the high estimation in which oats are held as a food-stuff. That the dissolution of the cell-membrane is due wholly and entirely to the cytohydrolyst of the food-stuff was proved by making a parallel series of experiments on animals fed in the one case with barley-meal which was destitute of cytohydrolysing power, and in the other case with the same meal to which a small amount of germinated grain had been previously added.In the first instance no destruction of the parenchymatous cell-wall took place in the animal's stomach ; whilst in the second case the vegetable membrane was completely dissolved in a very short time. The presence of a cytohydrolyst and its amount in the food of graiii- feeding animals is a factor, and, perhaps, a very important one, ill their nutrition, for the mow or less complete preliminary preparatioii of the food in the stomach before it passes into the intestine cannot be B matter of indifference to the animal physiologically.The experiments have a very important bearing on the lengthy in- vestigation carried out at Rothamsted, some years ago, on the relative value of malted and unmalted grain as a food for stock. The whole of the subject requires re-examination from n new point of view, and it does not seem at all unlikely that the supposed condimeiital value of malt, which has been insisted on by many agriculturists in the fscceof tlie Kot1i;iuisteci experiments, rniLj-, after all, lie a fact. 33 DISCCSSION. Mr. BROWN,ill reply to Professor Tilden, said that the eiizyiiie iii question was undoubtedly distinct from diastase and unable to attack starch. With reference to the questtion put by Professor Green, whether the caecum of herbivora was not the seat of t’he digeetion of the cellulose in the major portion of their food, he thought that it was clearly shown by Tappeiner’s experiments that this was the case.and that its digestion was effected through the agency of micro-organisms. He was unable at present to give any reply to Mi*. Cross’s question as to the behaviour of the different varieties of cellulose. 109. “ On the influence of oxygen and concentration on fermenta-tion.” By Adrian J. Brown. The author describes experiments on the reproductive power of yeast, from which it appears that all fermentable nutritive solutions encourage the increase in number of yeast cells to some fixed point beyond which they will not reproduce themselves ; and he sliows that if a greater number of cells be intiaoduced into a fermentable liquid than the liquid could originally develop, no increase in numbel.of cells takes place. As under coiiditioiis like these fermentation still proceeds vigorously, a number of disturbing factors which complicate the results obtained under ordinary cenditions may be eliminated by using non-multiplying yeast cells. A series of experiments are described in which fermentations were conducted in presence of large amounts of oxygen, wliilst at the same time duplicate experiments were made in which oxygen was excluded : the same number of non-multiplying yeast cells being used in both cases, and all the other conditions, such as temperature and agita- tion, &c., being kept constant.Under these circumstances it was found that both equal numbers of yeast cells and equal weightss in pre- seiice of oxyger, exercised moiw fei-mentutirc power tllm wheii uuex-posed to its influence. The author is unable to recoil& these rcsults mitli 31. Pasteur’s theory of fermentation. Experiments carried out with a fixed number of iion-increasing yeast cells also showed that the amount of sugar fermented in a given time by them did not depend on the concentration of the solu- tion, but that within the limits of 20 and 5 per cent. solutioris of dextrose, approximately the same weight of sugar was fermented. When the strength of a solutioii reaches 30 per cent. of dextrose fermentation proceeds much more slowl~-.110. “ Lirnettin.” By William A. Tilden, L).Sc., F.R.S. Liuiettin is tile name given by the rtuthr to a cry&dline suhtzluoe 34 deposited from the essential oil of the lime, originally described by him in conjunction with C. Rl. Beck (C.S. Tmns., 1890, 323). Fnrther investigation of its properties shows that, instead of tlie formula Cl6Hl4O6first attributed to it, limettin has the compositioii expressed by the molecular formula CllH1004,which requires nearly the same percentages of carbon and hydrogen. By the action of nitric acid it is converted into a nitro-derivative CIIH,(NO,)Oa, and by the action of bromine into a dibromo-derivative C11H8Br20a,while chlorine converts it into a trichloro-corn pound C11H,C1304. The dibromo-compound also exchanges the third atom of hydrogen for chlorine, giving CllH7Br2C104.Oxidising agents convert limet,tin into acetic or oxalic acid without definite inter- mediate products. Potash fusion produces from it phlorvglucol and acetic, but no other acid. Treatment with concentrated solution of hydrogen iodide causes the elimination of two methyl groups. Sulyhuric acid slightly diluted causes limettin to assimilate a mole-cule of water forming a, phenolic compound of which the diacetate was prepared and analysed. Limettin is not attacked by acetyl chloride, by phenylhydrazine or by sodium amalgam, and it gives no coloration with feryic chloride. It forms very pale-yellow, thin prisms, which melt at 147’5 ; it dissolves in alcohol, benzene, toluene and acetic acid pretty freely, but scarcely in water or in light peiroleum.Dilute solutions exhibit a beautiful violet fluoyescence. It seems to have the constitu- Further experiments are in progress. tion C6H3(OCH3),*c3~02. 111. “ The acid action of drawing papers.” By C. Beadle. Professor W. N. Hartley has recently communicated a note on this subject (these Proceedings, 1892, 19) which raises questions of con-siderable technical importance. The fact of the “ acidity ” of papers need not be discussed, and Professor Hartley’s contention that an acid constituent in the paper has a serious effect on “ water colouias ’’ applied to the paper I am not in a position to criticise. I merely wish to point out that the author is probably in error as to the cause of the acidity, which he takes to be a residue of sulphuric acid left in the “ fibre ” (rags) after the process of “ souring ” and washing.The mill where the “ Whatman” papers are made is sitnated at Maidstone, and the water used in the manufacture is the character- istically hard water of that district. The “ souring ” of tlie rags is followed by a long process of continuous washing in the “ engine,” and after some years’ experience of paper making in the Hentish district I am satisfied that no acid can survive this treatment. On the other hand, the papers are sized with gelatin and alum, 35 and it is to the presence of tthe latter constituent that the “ acidity ” is, in my opinion, due.In a recent examination of one of these papers I obtained, by treating with distilled water, an exhaust which showed “acidity” equal to 2.3 C.C. normal H2S04 per 100 grams paper, wing litm?bs as indicator in the titration, and yet this exhaust was Basic to methyZ orange. Sulphate of alumina, Al2,3SO4, being acid to methyl orange, the evidence is complete that tihe apparent “ acidity ” of the aqueous exhaiist is due to the presence of a basic sulphate of alumina (of. Jozcr. Xoc. Chem, Ind., 1891, 202). ADDITIONS TO THE LIBRARY. I. Donations. A Treat,ise on Chemistry, by €I.E. Roscoe and C. Schorlemmer. Vol. 111. Part VI. London 1892. From the Authors. Lac Ingol ; Recherches Medico-topographo-chimiques,par S. 8. Zaleski. Tomsk 1891. From the Author.U.S. Geological Survey :-Tenth Annual Report, 1888-89, by J. W. Powell; Part 1, Geology ; Part 2, Irrigation. Washington 1890. Bulletin. Nos. 62, 65, and 67-cjl. Washington 1890-31. Prom the Director of the Survey. 11. By Pairchase. Anorganische Chemie, von F. Krafft. Leipzig und Wien 1891. Methods of Gas Analysis, by W. Hemp]. Translated from the 2nd German Edition by L. M. Dennis. London 1892. The Chemistry of Iron and Steel Making, by IV-Mattien Williams. London 1890. Engineering Chemistry, by H. J. Phillips. London 1891. A System of Inorganic Chemistry, by W. Ramsay. London 1891. Solutions, by W. Ostwald. Translated from the 2nd edition of Ostwald’s Lehrbuch der xllgemeinen Chernie, by M. 21. P. Muir. London 1891.Fremy’s Encylop6ciie chimique. Tome 111, 13 cahier, 2 partie : Plomb et ses composes, par F. Parmentier. Tome V, 2 section, 2 partie. L’Or, par E. Cuinenge et E. Fuchs. Paris 1892. Chemische Technologie d er Gespinnstfasern, von 0. N. With. Lief. 1und 2. Braunschweig 1888 und 1891. ANNIVERSARY MEETING AND SECOND ANNIVERSARY DINNER. The Anniversary Meeting will be held at FOUTo’clocJc in the After-noon of Wednesday, March 30th next. It is arranged that on the evening of the same day the Fellows and their friends will dine together at the Whitehall Rooms, Hotel MBtropole. At the next meeting, on March 3rd, the followiiig papers will be read :-“ A rule for determining whether a given benzene mono-deriva- tive shall give a meta-di-derivntire or R mixture of ortho- and para- &-derivatives.” By Professor Crurn Brown and Dr. Gibson. “ The relative orienting effect of chlorine and Iiromine.” By Dr. Armstrong and Blr. Briggs. “ Contributions to our knowledge of the aconite alkaloids. “ Part 11. The alkaloids of true Aconifum napelZu.<.” By Professoi-I)unstan and Mr. Umney. “ Part 111. The properties of aconine. Conversion of sconine into aconitine.” By Professor Dunstan and Dr. Pa,ssmore. “ Note on the origin of the luminosity of coal-gas flames.” Bj-Wm. Foster, M.A. “ The volurrietlric estimation of mercury.” By Chapman Jones. HARRISON AND SONS, PRINTERS IN OEDINABY TO HER MAJESTY, ST. MARTIN’S LANE.
ISSN:0369-8718
DOI:10.1039/PL8920800029
出版商:RSC
年代:1892
数据来源: RSC
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