60 MILK AND THE PUBLIC HEALTH CHAP. 



The diphtheria bacillus grows readily in milk, the rnilk 

 remaining unchanged in appearance although an acid reaction 

 develops. The table of Eyre's, recorded above, shows how 

 rapidly this organism multiplies in sterile milk. 



Schottelius, 1 in his investigations, found that the diphtheria 

 bacillus grew better in raw than in sterilised milk, at both 

 room temperatures and at 3 7 C., the raw milk being obtained 

 direct from the udder. Feinberg has confirmed this, but Jensen, 

 on the other hand, found their growth was retarded in raw 

 fresh milk. 



In butter, according to Montefusco, the diphtheria bacillus 

 is killed after two days. The only observation which the 

 writer has found as to growth in cream or cheese is one of 

 Klein's, 2 who found that diphtheria bacilli inoculated into 

 sterile cream and sterile cheese, kept, part at 37 C. and 

 part at 20 C., were not recovered when examined for after 

 two weeks. 



Sp. cholerae grows rapidly in sterile milk without naked 

 eye change, but with the production of a little acid. In 

 ordinary market milk the acid reaction initially present, or 

 which rapidly develops, is prejudicial to its growth, as this 

 organism requires an alkaline medium in which to grow. The 

 results of investigations as to the viability of the cholera vibrio 

 in raw milk, show that it does not survive for long periods. 

 Thus, Cunningham could not find it after 24 hours, Uffelmann 

 found it after 3 but not after 40 hours, Friedrich not after 2 days, 

 Basenau not after 38 hours. On the other hand, Heim found 

 it to live 1 to 6 days. From the results obtained and from 

 the known inhibitory action of acid on its growth, it is clear 

 that the viability depends upon the temperature at which the 

 milk is kept and the rate at which acid develops. Klein ' 2 

 found it to live longer in milk at 7 12 C. than when 

 the milk was kept at 12-22 C. 



In butter, Heim 3 and others have shown that this organism 

 soon dies out, usually not living more than a few days ; although, 

 in one experiment, Heim records that they were found alive 

 after 49 days. Heim, Eowland, and other workers have 



1 Centralbl.f. Bakt., 1896, Abt. I. xx. p. 897. 



2 Report of Medical Officer, Local Government Board, 1899-1900, p. 577. 

 3 Arbeit a. d. Kaiserl. Gesundheitsamtc v. 1889, v. p. 294. 



