512 
statements, by incorrect, unsubstantiated, or exaggerated reports, and 
by alleged injurious effects to healthy cattle. 
Law “ has clearh" stated the question when he says : 
Many stock owners still entertain an ignorant and unwarranted dread of the 
tuberculin test. It is true that when recklessly used by ignorant and careless 
people it may be made a root of evil, yet as employed by the intelligent and 
careful expert it is not only perfectly safe, but it is the only known means of 
ascertaining approximately the actual number affected in a given herd. In 
most infected herds, living under what are in other respects good hygienic con- 
ditions, two-thirds or three-fourths are not to be detected without its aid. so 
that in clearing a herd from tuberculosis, and placing both herd and products 
above suspicion, the test becomes essential. 
***** * 
In skilled hands the tuberculin test will show at least nine-tenths of all cases 
of tuberculosis when other methods of diagnosis will not detect one-tenth. 
It is perfectly natural that there should be objection to its use 
among those who are not acquainted with its method of preparation 
or its properties; but it is difficult to explain the antagonism of farm- 
ers who are familiar with the facts connected with the manufacture 
and use of tuberculin. Probably the most popular objection to tuber- 
culin is that it is too searching, since it discovers cases in which the 
lesions are small and obscure. AVhile this fact is admitted, it should 
also be borne in mind that such a small lesion to-day may break down 
and become widely disseminated in a relatively short period. There- 
fore any cow affected with tuberculosis, even to a slight degree, must 
be considered as dangerous not only to the other animals in the herd 
but also to the consumer of her products. 
THE HABMLESSXESS OF TUBERCULIN. 
Furthermore, tuberculin must be considered as harmless for healthy 
animals in view of the results revealed by numerous tests covering 
vast number of animals. And it has also been clearA demonstrated 
that tuberculin interferes in no way with the milking function in 
healthy cattle ; neither in the quantity of milk nor in butter-fat value 
has any variation been detected. 
Xocard and Leclainche ^ state: 
Direct experiments and observations collected by thousands show that the 
tuberculin injections have no unfavorable effect. With healthy animals the 
system is indifferent to the inoculation ; with tuberculosis animals it causes 
only slight changes, which are not at all serious. 
“ Text Book of Veterinary Medicine, vol. 4, pp. 458, 465. Ithaca, N. Y., 1902, 
^ Les Maladies Microbiennes des Animaux, vol. 2, p, 85. Paris, 1903. 
