260 TUBERCULOSIS. 



reason why children are more often infected is perhaps 

 two-fold. They are usually fed almost exclusively upon 

 milk, and the very young of all species are most suscep- 

 tible to the disease. This question oE tuberculosis of 

 cattle is one of the most important matters with which 

 our country now has to deal, for it certainly exists to a 

 most alarming extent, and not in our own country alone, 

 but all over the world. To New York State belongs the 

 credit of passing the first law which, gave authority to 

 deal with the examination of cattle to determine the ex- 

 istence of tuberculosis,beginning in 1893 in a small way the 

 examination of cattle. It was found that Koch's lymph 

 or tuberculin (which is a culture fluid in which tubercle 

 bacilli have been grown) is so accurate as a means of 

 diagnosis that any competent veterinarian can point out 

 a diseased animal with absolute certainty. The action 

 of tuberculin is explained by the fact that the animal sys- 

 tem has a certain amount of toleration for all kinds of 

 poisons. The most p)owerful poison may be given to man 

 or animal in small doses without toxic effect. Most of 

 you are acquainted with the characteristic fever and chili 

 in advanced cases of consumption, which is caused by 

 the absorption of ptomaines and other poisonous sub- 

 stances from the degeneration of dead tuberculous mat- 

 ter in the system. In other words, where the disease is 

 already present, enough tuberculin is manufactured in 

 the system to overcome the toleration for it, and when a 

 fresh supply is injected there is a very decided toxic 

 effect produced. This effect is, of course, greater or less 

 in proportion to the extent of the disease. If it is in- 

 jected into a healthy animal or person in ordinary quan- 

 tity it is tolerated and gives no reaction. 



EXAMINATION Of CATTLE. 



During the year 1894 the New York State Board of 

 Health examined 22,000 cattle, and of this number 



IQS 



