310 STUDIES OX FERMRNTATIOX. 



tions ? It would, perhaps, be more natural to admit that in the 

 one case there is an adaptation to life with air, and in the other 

 case an adaptation to life without air ; each of these varieties 

 perishing when suddenly transferred from its habitual condition 

 to that of the other, whilst by a series of progressive changes 

 one might be modified into the other.* We know that in the 

 case of alcoholic ferments, although these can actually live with- 

 out air, propagation is wonderfully assisted by the presence of 

 minute quantities of air ; and certain experiments, which we 

 have not yet published, lead us to believe that, after having 

 lived without air, they cannot be suddenly exposed with impu- 

 nity to the influence of large quantities of oxygen. 



We must not forget, however, that aerobian torulae and 

 anatirobian ferments present an example of organisms appa- 

 rently identical, in which, however, we have not yet been able 

 to discover any ties of a common origin. Hence we were forced 

 to regard them as distinct species ; and so it is possible that 

 there may likewise be aerobian and anaerobian vibrios without 

 any transformation of the one into the other. 



The question has been raised whether vibrios, especially 

 those which we have shown to be the ferment of butyric and 

 many other fermentations, are, in their nature, animal or 

 vegetable. M. Ch. Robin attaches great importance to the 

 solution of this question, of which he speaks as follows f: — 

 " The determination of the nature, whether animal or vege- 

 table, of organisms, either as a whole or in respect to their 

 anatomical parts, assimilative or reproductive, is a problem 

 which has been capable of solution for a quarter of a century. 

 The method has been brought to a state of remarkable pre- 

 cision, experimentally, as well as in its theoretical aspects, 

 since those who devote their attention to the organic sciences 

 consider it indispensable in every observation and experiment 



* These doubts might easilj' bo removed by putting the matter to the 

 test of direct experiment. 



t EOBIN', Sur la nature des fermentations, &c. {Journal ch V Anatomie et 

 (Je la Fliysiologie, July and August, 1875, p. 386). 



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