EXPERIMENT STATION BULLETINS. 



469 



We obtain the following numbers for the rate of reproduction : 



H 94 minutes in 24 hours. 



G8 minutes in 24 hours. 



1 146 minutes in 36 hours. 



K 110 minutes in 24 hours. 



81 minutes in 24 hours. 

 L 106 minutes in 24 hours. 



The three best comparable numbers of H, K, and L, which were got- 

 ten by the same dilutions, 94, 110 and 106, agree fairly well. But in 

 all, tiie results do not check nearly as w^ell as in those of the young 

 cultures. That is not surprising; we have here the same experience 

 which every plant breeder has; by continuous cultivation under nearly 

 the same conditions a very homogenous strain is obtained. If no more 

 care is given to this strain, it will lose the homogenicity, all kinds of 

 varieties are found, and it takes a large number of generations to make 

 up for the degeneration in a comparatively short time. In this particu- 

 lar case, a new type had been formed from Bacterium A, a fast grow- 

 ing, but slowh' fermenting organism. 



TABLE XIY .—Degeneration of Strain II. 



*48 hours. 

 t73 hours. 



The experiment on the degeneration of lactic bacteria in milk was 

 rejieiited with Strain II, Avith the same result. The decrease of the fer- 

 menting capacity was not as great as with Strain a, but quite distinct. 

 The number of bacteria in the stock culture A decreased faster than was 



