August 21, 1890] 



NATURE 



407 



presented by the living cell and which attend digestion. As the 

 authors of a paper "On the Germination of the Gramineee " 

 (Chemical Society's Transactions, 1890, 458) have done me the 

 honour to accept several of my suggestions, 1 venture to regard 

 the opportunity as one which should not be lost of discussing 

 the terminology of fermentation phenomena. 



Changes such as a glucose undergoes when it is resolved into 

 carbon dioxide and ethyl alcohol take place under the influence 

 of the living organism, and there is every reason to believe only 

 -within the cell : they involve the formation of products con- 

 taining in the gross neither more nor less than the original 

 elements of the compound fermented ; and when the products 

 are compared with the compound from which they are derived, 

 it is seen that their production in all cases involves the separation 

 of carbon atoms which were directly united, and also consider- 

 able rearrangement of the constituent elements. 



Changes such as that which cane-sugar undergoes on inversion 

 take place not only within the cell but equally well without it 

 under the influence of a substance which, although not living, 

 is of vital origin : they appear always to involve the fixation of 

 the elements of water ; and the products of their action bear a 

 very simple relation to the original substance, viz. always that 

 if an alcohol to its ether, no separation of directly-united 

 carbon-atoms, or any molecular rearrangement such as attends 

 the former class of actions, taking place. The agents derived 

 from organisms which effect changes of this second kind are 

 spoken of as unorganized ferjnents ; changes of the first kind 

 are said to be conditioned by organized ferments, i.e. organisms. 



There is thus, at the outset, a difficulty in assigning a con- 

 sistent meaning to either term — fermentation or ferment ; diverse 

 phenomena produced by diverse agents being included under a 

 single designation. 



Fermentation. — The difficulty is in part met by restricting the 

 term fermentation to changes such as occur, for example, during 

 alcoholic fermentation ; and there would seem to be no occasion 

 10 apply it more widely so as to include changes of the second 

 kind, these, as before remarked, being apparently all cases of 

 simple hydrolysis. This is true, even if the explanation of 

 fermentation suggested by Baeyer in 1870 (cf. Ber., 1870, 63 ; 

 Journal of the Chemical Society, 1871, 331) be accepted, which 

 represents fermentation proper as the outcome of hydrolysis— an 

 explanation which the increase of knowledge in the interval en- 

 tirely favours ; inasmuch as hydrolysis takes place in the two 

 cases with different results, and afiects compounds of different 

 types. Moreover, it is to be noted that not only is it impossible to 

 represent the phenomena of fermentation proper as the outcome 

 of simple hydrolysis, but that also, in certain cases, synthetic as 

 well as analytic changes occur ; in the case of butyric fermenta- 

 tion, for example. In fact, in many instances, apparently two 

 series of concurrent changes take place : the one series involving 

 what, in the light of iSaeyer's explanation, may be termed 

 recurrent as distinguished from simple hydrolysis ; the other in- 

 volving the interaction of the molecules of one or more products 

 of this recurrent hydrolysis. There is thus an advantage in em- 

 ploying a somewhat empirical expression in connoting phenomena 

 which do not all conform to one absolute type, but which have a 

 common origin, as they are the outcome of protoplasmic activity, 

 especially as most fermentations are attended with evolution 

 of gas. 



But it is to be remembered that, whereas carbohydrates and 

 allied compounds such as glycerol, lactic acid, &c., are said to 

 MnA&xgo fermentation, the decomposition of albuminoids under 

 the influence of organisms is commonly termed putrefaction ; 

 this distinction, however, is made on account of the character of 

 the products, not because there is any reason to suppose that the 

 changes which occur are essentially different in character from 

 those which the carbohydrates undergo. The want of a term 

 indicative of the fact that the- action is one which takes place 

 under vital influence without reference to the character of the 

 change — equally applicable to simplifications such as occur 

 luring alcoholic fermentation and to complications such as occur 

 luring butyric fermentation — is also felt in the case of changes 

 uch as alcohol undergoes under the influence of Mycoderma 

 ucti and vini, or which ammonia undergoes on nitrification, and 

 in, the converse change of denitrification. Dr. W. Roberts has 

 proposed to speak of changes induced by enzymes {v. infra) as 

 cases of enzymosis ; the corresponding term zymosis might well 

 be employed as the synonym of fermentation, and would probably 

 lie found to be of more general application : thus alcohol may 

 be said to undergo oxidation by zymosis or zymic oxidation under 

 the influence oi Mycoderma aceti ; and in discussing putrefactive 



NO. T086, VOL. 42] 



changes, it would be possible to speak of zymic changes as 

 distinct from those arising from the unassisted interaction of the 

 zymic products. Zymosis is preferable to zymolysis, as the effect 

 is not always one of simplification. 



Ferments. — The expression ferment is more frequently than 

 not employed as the equivalent of unorganized ferment ; con- 

 sequently it is applied to the very agents which are incapable of 

 producing fermentation proper. This has been so generally felt 

 to be the case that several words have been coined in place of 

 unorganized ferment, notably zymase and enzyme (cf. Dr. W. 

 Roberts, Roy. Soc. Proc, 1881, xxxi. 145) : the objection may 

 be made to the former that it is indicative of vitality ; the latter, 

 however, is expressive, and serves only to indicate the vital 

 origin of the agent, thus differentiating it from agents such as 

 the mineral acids which act very similarly. 



Enzymic action or enzymosis ' — to use the phrase suggested 

 by Dr. Roberts — appears, as already remarked, always to involve 

 decomposition by means of water. On this account, in 1880, 

 in the second edition of my "Introduction to the Study of 

 Organic Chemistry " (Longmans ; footnote, p. 190) I put 

 forward the following suggestions : — 



"Decompositions like those of starch into dextrose, of cane- 

 sugar into dextrose and Isevulose, of the fats into glycerine and 

 an acid, or of ordinary ether into ethylic alcohol, which involve 

 the fixation of the elements of water, may all be said to be the 

 result of hydrolysis ; and those substances which, like sulphuric 

 acid, diastase, emulsin, &c., induce hydrolysis may be termed 

 hydrolytic agents or hydrolysis. The substance hydrolyzed is 

 the hydrolyte. The mere fixation of the elements of water, un- 

 accompanied by decomposition, as in the conversion of ethylenic 

 oxide into glycol, C0H4O + OHo = C2H4(OH)2, maybe termed 

 hydration in contradistinction." 



It is usually necessary to employ a specific enzyme (hydrolyst), 

 or one of a very limited number, to effect the hydrolysis of any 

 particular hydrolyte, and hence physiologists are in the habit of 

 speaking of amylolytic ferments, proteolytic {ermenis, SiC, mean- 

 ing ferments capable of splitting up starch, proteids, &c. But 

 the terms amylolytic, proteolytic, &c., are confusing to the student 

 who has learnt that electrolysis signifies splitting up by means of 

 electricity, and hydrolysis splitting up by means nf water — not 

 the splitting up of electricity or of water. As electrolysis and 

 even hydrolysis are well-established terms which it would scarcely 

 be politic to alter, it appears highly desirable to abandon the use 

 of terms such as amylolytic, proteolytic, &c., and I would suggest 

 that an enzyme capable of inducing the hydrolysis of starch 

 should be termed an amylo-hydrolyst ; one which aftects albu- 

 minoids, a proteid-hydrolyst ; one which affects fats, a glyceride- 

 hydrolyst. 



One case remains in which the use of the term ferment cannot 

 be avoided by the adoption of this proposition — that of the 

 so-called rennet ferment. It may well be that this is also a 

 hydrolyst, and that in all cases the formation of a curd, clot, or 

 coagulum initially involves hydrolysis— or, perhaps, hydration 

 merely— and the consequent interaction of molecules of the pro- 

 duct or products ; but of this we know nothing at present, and 

 the observed phenomena are of so different a character that it is 

 desirable to connote such changes by a distinct expression. I 

 would suggest that we should term the rennets thrombogettic 

 enzymes or thrombogens. Henry E. Armstrong. 



SCIENTIFIC SERIALS. 



L! Anthropologic, sous la direction de MM. Cartailhac, Hamy, et 

 Topinard, tome i.. No. 2 (Paris, 1890).— The covered mortuary - 

 chambers at Les Mureaux (Seine-et-Oise), by Dr. Verneau. 

 Through the accidental displacement of the soil in a field at 

 Les Mureaux an important discovery was made in the winter of 

 1888-89 of a subterranean sepulchral passage, a so-called a//<?^ 

 couverte, which was densely packed with human bones, inter- 

 mingled with various stone, bone, and other objects. As in 

 other constructions of the kind, this mortuary passage was 

 divided into two paved and walled-in chambers, varying in 

 width from r85 m. to 2'io m. Owing to the thickness of the 

 stone walls dividing these chambers, considerable labour must 

 have been required to effect an entrance whenever a fresh 

 burial took place. It would appear that sixty or more skeletons 

 had been deposited in these chambers, but unfortunately many 



• Sheridan Lea's zymolysis (cf. Journal 0/ Physiolo^O't 

 open to the objection above made to zymase. 



xi. 254) 



