TRANSLATOR'S PREFACE. 



The production of market milk is a rapidly growing 

 industry. The demand for milk in cities is continually 

 increasing and tliere is reason to believe that the rate 

 of increase will advance. 



The milcli cow transmutes the pasturage and forage 

 of the farm into edible protein, lactose and fat — into 

 units of nutriment for man — at less than one-half the 

 cost of similar units in beef produced by the steer. 

 Milk is not only the most economical but, when pure and 

 undefiled, it is among tlic most wholesome and it is 

 the most easily digestible of all foods of animal origin. 

 These are the strongest possible reasons for its extended 

 use. 



On the other hand, there is no other food that, under 

 ordinary conditions, is so exposed to contamination, 

 that is so easily contaminated or that so fosters contami- 

 nation as milk. Hence the necessity for the study of 

 milk hygiene. 



The subject is a broad one. Milk hygiene involves 

 some knowledge of the physiology of cows, especially 

 with relation to breeding, lactation and nutrition; of 

 comparative pathology, particularly the various dis- 

 eases of the udder of the cow, the abnonnal conditions 

 that affect milk seci'etion, and the infectious diseases 

 of cattle and of man that may be transmitted I_iy milk; 

 of bacteriology, in regard to the pathogenic organisms 

 and the saprophytes that occur in milk, their etfects, 

 their behavior under various conditions and especially 

 at different temperatures ; of the chemistry of milk and 

 its adulterations and, besides these, there must be added 



