12 Dairy Bacteriology. 



its germ content, so that the normal ground water, like 

 the deeper soil layers, contains practically no bacterial life. 

 Springs therefore are relatively deficient in germ life, ex- 

 cept as they become infected with soil organisms, as the 

 water issues from the soil. Water may serve to dissem- 

 inate certain infectious diseases as typhoid fever and cholera 

 among human beings, and a number of animal maladies. 



While the inner tissues of healthy animals are free from 

 bacteria, the natural passages as the respiratory and digest- 

 ive tracts, baing in more direct contact with the exterior, be- 

 come more readily infected. This is particularly true with 

 reference to the intestinal tract, for in the undigested 

 residue, bacterial activity is at a maximum. The result is 

 that fecal matter contains enormous numbers of organ- 

 isms so that the possibility of pollution of any food medium 

 such as milk with such material is sure to introduce ele- 

 ments that seriously affect the quality of the product. 



