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 one of a somewhat obscure 

 type. The four definite diseases are tuberculosis, diph- 

 theria, scarlet fever, and typhoid fever. The other one 

 referred to is the indefinite series of intestinal troubles 

 known as summer complaint, summer diarrhea, cholera 

 infantnm, etc. These are all characterized by the pres- 

 ence of diarrhea, and are particularly common in warm 

 weather. 



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 may be dangerous ; 



