Contamination of Milk. 



29 



The ready infection 1 of the external opening of the 

 milk duct gives an opportunity for bacteria to plant them- 

 selves on a moist mucous surface, and the result is, that 



some organisms, at 

 least, find it possi- 

 ble to penetrate the 

 milk duct and so 

 enter the milk cis- 

 tern. When once 

 this reservoir is in- 

 fected, further 

 spread can be easily 

 made, even into the 

 glandular portion 

 of the udder. 2 In 

 such a habitat, ideal 

 conditions would 

 seem to exist, at 

 least, for the faculta- 

 tive anaerobic type 

 of bacteria. Moist- 

 ture, warmth, suffi- 

 cient and nutritious 

 food, give optimum 

 conditions for de- 

 velopment, but 

 these may, in part 



FIG. 8. Section of udder, showing teat, milk cis- , , , , 

 tern and secreting tissue (Moore and Ward). at least > be 



by the fact 



that 



1 According to Jos. Simon (Diss. Hyg. Inst. Erlangen, 1898) the udder is sterile 

 except at outer opening. 

 8 Moore and Ward, Bull. 153, Cornell Expt. Stat, Jan., 1899. 



