FERMENTATION. 131 



egg albumen. . . . They must, accordingly, be regarded as specific in their 

 nature, depending on the specific nature of the protoplasm of which they 

 are merely further differentiations." 



Micro-organisms, when grown under such conditions that 

 oxygen cannot gain access to them under conditions of 

 anaerobiosis usually appear incapable of developing their 

 separable peptonizing enzyme function, as they are no longer 

 able to liquefy the gelatine in which they are growing. The 

 fact that this separable enzyme function could be kept in 

 temporary abeyance was utilized by Chantemesse and Widal, 

 to prevent the liquefaction that takes place in plate cultiva- 

 tions where a certain specific organism requires a considerable 

 time for its complete development. By adding dilute carbolic 

 acid to their nutrient medium they found that the peptonizing 

 power of the organisms was interfered with ; whilst if the 

 carbolic acid solution was sufficiently weak, even the more 

 delicate organisms still retained sufficient vitality to enable 

 them to grow on the surface of the carbolized gelatine. 



Having corroborated the above observations, Hueppe and 

 Wood sought to obtain the same results while avoiding the 

 dangers resulting from the use of such a substance as carbolic 

 acid, by offering for the nutrition of the organism a certain 

 preparation of a material which would enable it to develop 

 the diastatic, instead of the peptonizing ferment ; and, by 

 adding glycerine to the gelatine, they found, as they expected, 

 that Lauder Brunton's and M'Fadyean's experiments were 

 practically repeated. The organisms feeding on the glycerine 

 did not in most cases attack the gelatine, and the peptonizing 

 became exchanged for a diastatic ferment ; plate cultivations 

 were not so rapidly liquefied, and bacilli of very slow growth 

 could thus be separated from impure cultivations, in which 

 organisms that ordinarily exert a liquefying or peptonizing 

 function were present in considerable numbers. 



Our knowledge of most other fermentations, although 

 being gradually increased, is still in a somewhat nebulous 

 condition, for the reason that no one has as yet (with 

 the exception of those who have worked at the matter 

 from the industrial point of view) taken up the matter 

 thoroughly since it became possible to obtain pure cultiva- 

 tions of any single organism, the whole energy of bacterio- 

 logists having been diverted to the consideration of the very 

 important questions that have come up to be answered in 



