38 Agricultural Bacteriology. 



necessary that it be present in the former than in the 

 latter. 



Essentials in the production of clean milk. The 

 statement is frequently made that the production of 

 clean milk means expensive stables, elaborate equip- 

 ment, and much expenditure of time and labor, but 

 such ideas are far from correct. The essential condi- 

 tions are (1) clean cows, clean because they are not al- 

 lowed to lie in their own excreta, or are not forced to 

 wade in muddy yards; (2) clean utensils, well washed 

 and sterilized; (3) clean barns; (4) clean men who take 

 pleasure in keeping their stables and animals clean, 

 and who recognize the important sources of contamina- 

 tion of milk and avoid them, while omitting the non- 

 essential things that figure so largely in many of the 

 directions for the production of clean milk. 



The expense of producing clean milk need be but 

 slightly more than that involved in the production 

 of the ordinary grade of milk. The same animals, the 

 same feed, the same time spent in feeding and in caring 

 for the cattle, supplemented by a slight amount of at- 

 tention directed to the important points is all that is 

 needed. 



Infection of milk with disease-producing bacteria. 

 Milk is often a means by which disease is spread. It 

 may serve to convey the disease-producing germs 

 from one animal to another, from the cow to man, or 

 from one person to another in the case of some diseases 

 not found in the cow. Of the diseases common to man 

 and cattle, tuberculosis is the most important. Of the 

 diseases found only in man but which are spread by 

 means of milk, typhoid fever and diphtheria are of 

 most concern. 



