MILK AS A DISTRIBUTER OF DISEASE 227 



Milk. Milk is a means of distributing certain diseases ; 

 not, indeed, a vehicle by which a contagious disease in a 

 household is carried from one member of the family to 

 another, but rather a source by which diseases from out- 

 side may find entrance into the family. The diseases com- 

 monly attributable to milk are not very numerous, four of 

 them being very definite and two of a somewhat obscure 

 type. The four definite diseases are tubercnlosis, diph- 

 theria, scarlet fever, and typhoid fever. Of the other two 

 referred to, one is the indefinite series of intestinal troubles 

 known as snmmer complaint, summer diarrhea, cholera infati^ 

 turn, etc., all characterized by the presence of diarrhea, and 

 particularly common in warm weather ; the other is a type 

 of tonsilitis, probably distributed in the same way. 



There is no doubt that all of these diseases are occa- 

 sionally distributed by milk. The one most commonly 

 attributed to this source is typhoid fever, and many 

 instances have been recorded where epidemics of typhoid 

 have been due directly to milk contaminated with typhoid- 

 fever bacteria. Epidemics of diphtheria and scarlet fever 

 have also been traced to the same source, though more 

 rarely. The question whether any considerable amount 

 of tuberculosis is attributable to milk has not been 

 settled positively, but the probability seems to be that 

 milk is a source of this disease, especially for young chil- 

 dren. Pure milk, however, is never the cause of any 

 of these troubles. Milk fresh from a healthy cow is 

 never the source of any of the diseases above mentioned, 

 nor indeed do any of them, except tuberculosis, come 

 directly from the animal producing the milk. Some 

 cows have tuberculosis and their milk mny be dangerous ; 



