250 MILK 



eluded from this observation that the bacteria multiplied at a 

 greater rate in boiled milk than in raw milk. Fokker's work 

 stimulated a number of other investigators to take up the problem. 



The results are not concordant, and while there are those who 

 firmly believe in the existence of a germicidal property in fresh 

 cow's milk, even though a feeble one, others maintain that bac- 

 tericidal substances do not exist in milk. 



Ehrlich and Brieger in 1893 demonstrated that antitoxins and 

 bactericidal substances may be transmitted through milk. Uffel- 

 mann, Park, Hunziker, Koning, Kolle and his co-workers, and 

 Hippius are among those who believe in the presence of bacteri- 

 cidal substances in milk. 



Park does not think that the germicidal effect is of sufficient 

 intensity to be of practical value. Kolle and his collaborators 

 carried on extensive experiments which indicate that milk has a 

 bactericidal property which affects cholera spirilla, but does not 

 affect Bacillus typhosus, B. dysenteriae, B. coli, and B. enteritidis. 

 However, according to these authors, fresh milk has a restraining 

 property for dysentery bacilli, but in small measure only and in 

 negligible quantity for Bacillus typhosus, B. paratyphosus, B. 

 coli, and B. enteritidis. 



Marshall found that the number of bacteria in fresh milk may 

 be reduced to one-fortieth, Hunziker to one-tenth the original 

 number, while Klimmer noted a less marked reduction, and con- 

 cluded that bacteria are merely restrained, not destroyed. 



Hunziker's work not only confirmed the presence of a germi- 

 cidal property in fresh milk, but showed that it was more marked 

 although of short duration at 37 C. than at lower temperature. 



While Hesse recorded the destruction of cholera spirilla in 

 fresh milk, Basenau took the opposite view, claiming that cholera 

 spirilla multiply readily in fresh milk. 



More recently v. Behring has claimed that milk possesses a 

 bactericidal property similar to that of blood, and that this 

 property is enfeebled by heating the milk to 60 C. for thirty 

 minutes. He thinks that heated milk, having had its immune 

 bodies destroyed or diminished, is not suitable for infant -feeding. 



St. John and Pennington found that heating to 79 C. de- 

 stroyed the restraining property of fresh milk, and concluded 

 that pasteurized milk permits greater multiplication of bacteria 

 than does raw milk. Ayers and Johnson hold a different view 

 and have stated that when the initial number of bacteria in pas- 

 teurized and raw milk is approximately alike the rate of multiplica- 

 tion is also similar. It should be remembered, however, that if 

 there is any difference in the rate of growth of bacteria in raw and 

 pasteurized milk, this phenomenon would be manifest only when 



