198 AGRICULTURE OF MAINE. 



Third, milk can and does affect the pubHc health adversely 

 by serving as the transmitting medium through which infectious 

 diseases peculiar to mankind alone are carried from one per- 

 son to another. 



Fourth, milk, more than any single article of diet, constantly 

 helps to sustain human life and, owing to certain peculiar qual- 

 ities of milk as a food, it is safe to say that among young in- 

 fants and invalid adults milk in thousands of instances every 

 year in the United States saves human lives that otherwise 

 must have been lost. 



I. TRANSMISSION OF DISEASES OF THE COW TO HUMAN BEINGS. 



For practical purposes the only disease that deserves our con- 

 sideration under this subject is that of bovine tuberculosis. In 

 times past there has been an enormous amount of controversy 

 and investigation over the question of whether or not bovine 

 tuberculosis could be transmitted to and produce the disease 

 tuberculosis in human beings. As a result of all this work and 

 investigation certain statements can now be made with a much 

 greater degree of certainty than was the case a few years ago. 

 The facts now seem to indicate that bovine tuberculosis is 

 transmitted to human beings almost exclusively in the first few 

 years of life and is transmitted directly through cow's milk, 

 although it is equally possible for it to be transmitted by ice 

 cream or butter. 



It is now estimated that perhaps seven per cent of tubercu- 

 losis in human beings is of bovine origin. For children under 

 five years the best estimates are in the neighborhood of thirty- 

 three per cent. It is also believed that for the most part the 

 bovine or cattle variety of tuberculosis manifests itself in the 

 human race as the non-pulmonary types of tuberculosis; that is 

 to say, tuberculosis of the bones, joints and internal organs, 

 including tubercular meningitis. Hence, it would seem proba- 

 ble that whenever there is an increase in cattle tuberculosis 

 there must be an increase in these forms of human tuberculosis 

 other than consumption. 



It is not within my province to go into the question or thor- 

 oughly discuss the great economic loss to the dairy interests 

 itself from bovine tuberculosis in dairy herds. 



