BACTERIOLOGY OF WATER AND MILK 179 



explained the large number on the supposition that clumps or 

 colonies of bacteria had been washed from the teat where they 

 had multiplied into the milk. Eotch 3 presented a paper giv- 

 ing the results of experiments to determine the number of 

 bacteria in freshly drawn milk. The fore-milk and the milk 

 drawn near the close of milking were taken, and also the milk 

 drawn through a sterile cannula passed into the milk duct 

 nearly if not quite through the teat. His findings were that 

 practically sterile milk could be obtained by rejecting the first 

 or fore-milk from each teat. Moore 4 examined milk from 

 each quarter of the udder of nine cows. He found from a 

 very few (0 to 10) bacteria in a cubic centimeter to 8,400 per 

 cc. in the first milk and as many as 2,400 in the last. Plate 

 cultures made from the last milk from several quarters re- 

 mained sterile. In all, 20 apparently different species were 

 isolated. 



Source of bacteria in milk.. Bacteria gain entrance to 

 milk from two sources. (1) From the ducts of the teat and 

 udder. The bacteria that become localized in the udder itself 

 are usually restricted to micrococci and occasionally strepto- 

 cocci. 5 Rarely other bacteria become temporarily localized in 

 the udder.* The species vary according to the environment 

 and care of the cows. In case of disease affecting the general 

 system or localized in the udder such as anthrax and tubercu- 

 losis the bacteria causing them may also appear in the milk. 



3 Rotch. Trans. Asso. of American Phys., Vol. IX (1894) p. 185. 



4 Moore. Annual report B. A. I., U. S. Dept. Agric., 1895-6, p. 261. 



5 Moore. Trans, of the Society for the promotion of agricul- 

 tural sciences, 1899, p. 110. 



Reed and Ward. Am. Medicine, Vol. VII (1903) p. 256. 



Ward. Cornell Univ. Agric. Exp. Station, Bulletin No. 178, 

 1900. 



* Moore and Ward found a bacillus belonging to the colon group 

 that had invaded the udders of a large percentage of the cows in 

 a dairy. This bacillus caused a bad taint to the cheese made from 

 the milk. The udders were washed with a disinfectant and the 

 stable thoroughly cleansed and disinfected at short intervals. After 

 some months the bacillus was eliminated from all the udders. (Bul- 

 letin No. 158 Cornell Univ. Exp. Station, 1899.) 



