NINTH ANNUAL YEAR BOOK— PART X 471 
spread to man removed. Tuberculin may therefore be considered a most 
beneficial discovery for the stock raiser. Strange to say, many of these 
men have been incredulous, antagonistic, or prejudiced against the tu- 
berculin test by misinterpreting published statesmonts, by incorrect un- 
substantiated, or exaggerated reports, and by alleged injurious effects 
to healthy cattle. 
Law has clearly stated the question when he says: 
"Many stock owners sitll 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 kno.vn 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 conditions two-thirds or three-fourths are 
not to be detected vathout its aid, so that in clearing a herd from tuber- 
culosis and placing both herd and products above suspicion the test be- 
comes essential. In skilled hands the tuberculin test will show at least 
nine-tenths of all cases of tuberculosis w'hen 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 farmers who 
are familiar with the facts connected with the manufacture and use of 
tuberculin. Probably the most popular objection to tuberculin is that 
it is too searching, since it discovers cases in which the lesions are small 
and obscure. While this fact is admitted, it should also be borne in 
mind that such a small lesion today may break down and become widely 
disseminated in a relatively short period. Therefore any cow affected 
V. ith 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. 
In 1898, Bang, of Copenhagen, one of the highest European authorities, 
in his paper presented to the Congress for the Study of Human and Ani- 
mal Tuberculosis, at Paris, said: 
"Numerous tests made in almost every civilized country have demon- 
strated that in the majority of cases tuberculin is an excellent means for 
diagnosing, the existence or the non-existence of the disease, but giving 
us no positive information as to the extent to which the disease has 
progressed. When tuberculin produces a typical reaction we may be 
almost sure that there exists in the body of the animal a tubercular 
process. The cases in which a careful examiner has not succeeded in 
finding it are very rare, and I am led to believe that when, notwithstand- 
ing all the pains taken, it has escaped discovery, the reason is that it is 
located in a portion of the body that is particularly inaccessible. Never- 
theless, it is not to be denied that a fever, entirely accidental and of short 
duration, may in some rare cases have simulated a reaction. How'ever this 
may be, the error committed in wrongly condemning an occasional ani- 
mal for tuberculosis is of no practical consequence. 
