.Milk Fermentations. 57 



It is a wide- spread belief that thunder-storms cause the 

 premature souring of milk. Numerous experiments have 

 been conducted along these lines, and the general con- 

 clusion is that neither the electric discharge nor shock 

 due to thunder exert any effect on the development of 

 acid, but that the atmospheric conditions usually incident 

 to a thunder-storm are such as permit a more rapid bac- 

 terial growth. 



The lactic acid fermentation is produced by a large 

 number of different kinds of bacteria, although in the 

 spontaneous coagulation of milk, it is now believed that 

 a very widely distributed species is responsible for the 

 most of it. This organism was first described in a com- 

 plete manner by Hiippe 1 and called by him B. acidi lac- 

 tici. Giinther & Thierf elder 2 working on the spontaneous 

 souring of milk in the neighborhood of Berlin found 

 what they think is the same germ. Esten 3 , in this 

 country, studied milks from thirty different localities in 

 New England and the Middle States. He found a germ 

 in all but two cases that agreed in general with Giinther 's 

 description. Dinwiddie 4 , studying the same question in 

 Arkansas, arrives at the same conclusion. This pre- 

 ponderance of evidence makes it quite probable that there 

 is a widely distributed germ that is concerned in this 

 change although there are numerous other forms 5 that 

 are associated with this type of decomposition. Conn 

 and Aikman refer to the fact that over 100 species are 

 already known. It is fair to presume, however, that a 

 careful comparative study of these would show that 



1 Huppe, Mitt. a. d. k. Gesund. Amte, 2: 309, 1884. 



2 Giinther & Thierfelder, Arch. f. Hyg., 25: 164. 

 3 Esten, 9th Kept. Storrs Expt. Stat., p. 44, 1896. 



4 Dinwiddie, Ark. Expt. Stat., Bull. 45, May, 1897. 

 5 Kayser, Ann. de 1'Inst. Past., 10: 737. 



