2030 Journal of Applied Microscopy 



milk of ten healthy cows, isolated 16 distinct species of bacteria, some of which 

 were common to both the first and last milk, and others to only one of these. 

 All the micro-organisms found were bacteria, and none were found which 

 produced gas. 



H. L. Russell,^ in his text-book on Dairy Bacteriology published in 1894, 

 states- that he has found an average of 2800 germs per c. c. in the fore milk, 

 while the average of the remainder of the milk only had 330 germs per c. c. In 

 characterizing these, he says that " the number of species is usually small, one 

 or two kinds usually predominating to a large degree. Those that are com- 

 monly found are those that produce lactic acid, as these microbes find in milk 

 the best medium for their growth." 



Gosta Grotenfeldt,® however, in his text-book on the Principles of Modern 

 Dairy Practice, reasserts the statement of von Freudenreich, that when the milk 

 is drawn from the udder of a healthy cow, it is germ-free, or sterile. 



Dr. T. M. Rotch*^ concludes, from the examination of the bacteria found in 

 four cows' milk, that the bacteria do not necessarily come from external sources, 

 but that they may also come from some part of the milk tract between the udder 

 and the end of the teat. The few colonies, however, obtained in the plates from 

 the latter half of the milkings are considered as possible contaminations between 

 the " cow " and the " plates.' 



V. A. Moore ^ states that in investigations made upon this subject, he found 

 that, in addition to the bacteria in the fore milk, the last milk from at least one- 

 quarter of the udder in every case contained bacteria. 



H. W. Conn,'' reviewing this subject, says that the different results of many 

 of these early experiments is due to the small quantities of milk taken, while in 

 the latter experiments large quantities have been taken. He adds, " Undoubt- 

 edly the milk gland of the healthy cow produces milk which is uncontaminated 

 with bacteria, but the large calibre of the milk ducts makes it possible for bac- 

 teria to grow in the duct to considerable extent, so that it becomes a matter of 

 extreme difficulty to obtain milk from the cow, even with the greatest precautions, 

 which shall not be contaminated." 



Harrison,^'' in a report of investigations upon this subject, states, "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 open- 

 ing 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 1000 to 

 3000 in the after milk. 



Experiments have also been conducted on human milk by Palleske,^ ^ Honig- 

 mann,^2 Knochenstiern,^^ and Ringel,^^ and 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 Veranus A. Moore 

 and Archibald R. Ward^-^ of Cornell University. They investigated the source 

 of a gas and taint-producing bacterium in cheese curd, in 1897, 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 



