472 Transactions of the Canadian Institute. [Vol. VII. 



stated. " When milking is done there remains in the teat of the cow a 

 little milk that affords nourishment to any bacteria that may come in 

 contact with it through the opening at the end of the teat." The 

 average of a number of analyses made by him shows the presence of 

 18,000 to 54,000 germs in the fore-milk, and 1,000 to 3,000 in the after- 

 milk. 



Experiments have also been conducted on human milk by Pal- 

 leske,^^ Honigmann,^^ Knochenstiern,^ and Ringel,^^ but all of these have 

 independently found it impossible to get human milk from the mammary 

 gland in such a way as to be sterile. 



The most recent work upon this subject has been done by Moore 

 and Ward,^'' of Cornell University. They investigated the source of a 

 gas and taint producing bacterium in cheese curd for a certain factory 

 that was troubled with " gassy curd." They easily located the trouble 

 in the herd of a particular patron. On inquiring into the history of the 

 herd it was ascertained that at the time of parturition, the placentae had 

 been retained by a number of cows, and these had been allowed to 

 decompose in the uterus. It was soon after this that the "gassy curd " 

 began to appear. A thorough bacteriological examination located the 

 bacilius which was the cause of the "gassy curd " in the udders of the 

 cows of the herd ; and it seemed very probable, though, of course, not 

 demonstrable, that it had gained access to the udders from the decaying 

 placentae. 



Subsequent to this, Ward conducted further experiments, and in an 

 article on " The Persistence of Bacteria in the Milk-Ducts of the Cow's 

 Udder,"*^ he concludes, (i) " certain species of bacteria are normally per- 

 sistent in particular quarters of the udder for considerable periods of 

 time, and (2) it is possible for bacteria to remain in the normal udder 

 and not be ejected along^with the milk." These conclusions controvert 

 the statement previously made by Von Freudenreich and Grotenfelt 

 that the milk-ducts are always sterile at the close of milking, becoming 

 tenanted from the outside alone by organisms which chance to come into 

 contact with the end of the duct. 



The results of still later investigations by the same author are pub- 

 lished in a bulletin on the '' Invasion of the Udder by Bacteria."^^ In 

 these investigations a bacteriological examination was made of the 

 udders of milch cows slaughtered after reacting to the tuberculin test. 

 In all cases the udders were perfectly normal. Just before slaughtering 

 the animals were milked as^thoroughly as possible and samples of the 

 milk taken, and a bacteriological examination made. After slaughter- 



