SANITARY RELATIONS. 55 



distribution of disease, the influence taking place 

 through several channels. 



In the first place, dairy cattle are subject to several 

 infectious diseases which are communicable to man and 

 virulent in their effects. The most important of these is 

 tuberculosis. The etiology of this affection is now clear. 

 It is dependent on the development of a minute organ- 

 ism. The tendency at the present time is to the view 

 that the keeping of dairy cattle is a fruitful cause of the 

 spread of this disease. The specific germ of tuberculo- 

 sis may be conveyed both in meat and milk and since 

 the infection of the animal is not always recognised 

 promptly, a most insidious source of danger exists. 

 Other infectious and dangerous diseases e.g. scarlet fever, 

 diphtheria and typhoid fever, may be conveyed by milk. 



The common methods of 'adulterating milk, namely, 

 by abstracting fat or adding water, diminish the food 

 value but there has been great exaggeration of the im- 

 portance of these changes. It can scarcely be sound 

 to declare, as has occasionally been done by those en- 

 gaged in promoting sanitary legislation, that milk re- 

 duced in fat by legitimate processes or even watered to 

 a considerable extent is unwholesome. It is occasion- 

 ally stated that the digestion of the proteids of milk is 

 dependent on the presence of a certain amount of fat, 

 but the experimental or clinical evidence of this is ap- 

 parently not precise. Several competent authorities, 

 e. g., Vieth, Ufifelmann and Hartshorne, have unhesita- 

 tingly declared even closely skimmed milk to be 

 wholesome. As regards watered milk, it would be pre- 



