XV] ANAEROBIC BACILLI 393 



are exposed to the light, numerous gas bubbles rise up and 

 collect on the surface. A large number of subcultures in 

 various media were made from the primary anaerobic sugar 

 gelatine cultures and of the results the following deserve 

 special mention. 



(a) The rapidity of Uquefaction of the sugar gelatine by 

 the growth stands in an inverse ratio to the amount of gas 

 bubbles escaping through the gelatine as the growth pro- 

 ceeds. If, after inoculation of the sugar gelatine by stab, 

 there are found, after one or two days' incubation, nume- 

 rous gas bubbles distributed in the upper part of the 

 gelatine and escaping to the free surface, it may be pre- 

 dicted with certainty that the growth in, and the liquefaction 

 of, the gelatine in such a culture will proceed very slowly ; 

 and conversely, if after one or two days' incubation the 

 progress of liquefaction in the depth (after inoculation of 

 the depth) is conspicuous, there is very little or nothing to 

 be seen of gas bubbles on the surface. 



(6) The formation of spores stands in direct relation to 

 the rapidity of liquefaction ; in tubes in which the growth 

 and the liquefaction proceed very slowly, there are at no 

 time spores formed in the bacilli ; in old cultures of this 

 kind the bacilli are found as longer or shorter threads, some 

 undergoing involution and death by granular disintegration. 

 Whereas, in tubes in which liquefaction proceeds rapidly — 

 the whole of the gelatine liquefied in two to three days — 

 there is always copious spore formation. 



(<:) Milk inoculated with the bacillus and incubated at 

 37° C. shows, as a rule, already after twenty-four hours, 

 sometimes a little later, distinct changes consisting in the 

 separation of flocculi of coagulated casein from the slightly 

 turbid whey, numerous gas bubbles being present in the 

 creamy layer on the surface ; after forty-eight hours the 



