SANITARY MILK PRODUCTION 145 



Bacteria Derived from the Udder. Lister, according to Harding and 

 Wilson, made the first observations on the bacterial content of milk from 

 the udder and upon the results of his determinations on two small samples, 

 came the belief that milk within the healthy udder is germ-free. Work 

 by Lehmann and his pupil Schulz, in 1890, showed that fore-milk con- 

 tained many bacteria, middle-milk fewer and the stoppings still less. In 

 this country Moore confirmed these results. He and his pupil Ward made 

 examinations of excised tissue from different parts of functioning udders 

 of freshly slaughtered milch cows and were able to demonstrate bacteria 

 in the finer ramifications of the milk canal as well as in other parts of the 

 udder. At another time they showed that the organisms which gave rise 

 to gas and taint in a cheese curd originated in the udder. The bacteria 

 work their way from the outside, up the teat canal into the milk cistern 

 and thence into the milk canals. It is also possible but unusual for 

 bacteria to find their way into the milk within the udder from the blood 

 of the cow. 



Bergey of the University of Pennsylvania, in the summer of 1903, 

 studied the number and nature of bacteria in milk as it comes from the 

 udder. Two hundred and seventy-two samples were examined and the 

 bacteria found varied from to 93,100 per cubic centimeter. Of the 

 entire number of samples collected directly from the udder 87, or 32 per 

 cent., contained no bacteria; 118, or 43.64 per cent., contained less than 

 500 bacteria per cubic centimeter and 28, or 10.29 per cent., contained 

 over 5,000 bacteria per cubic centimeter. 



He also examined the milk from each of the four quarters of 20 cows 

 and obtained results such as those in Table 40. 



TABLE 40. BACTERIAL CONTENT OF MILK FROM FOUR QUARTERS OF Cows (BERGEY) 



Cow Quarter of the udder Bacteria per cubic centi- 

 meter 



9 Right fore 75 



Left fore 



Right hind 



Left hind 



6 Right fore 75 



Left fore 25 



Right hind 150 



Left hind 25 



Right fore 3,400 



14 Left fore 7,425 



Right hind 4,200 



Left hind 1,900 

 10 



