172 
LEONARD PEARSON. 
that has been heated to 185° F., they will remain free from 
tuberculosis. 
Tuberculin as a Diagnostic Agent .—The prevailing- opinion 
as to the accuracy of tuberculin as a diagnostic agent is amply 
sustained and it is established that the use of tuberculin fur¬ 
nishes by far the most accurate means of detecting tuberculosis 
and permitting the inspector to separate the healthy and diseased 
cattle. It is made clear that the degree of reaction does not in¬ 
dicate the extent to which an animal is diseased and that a high 
reaction may sometimes occur in an animal that is but slightly 
affected, and it is stated that from the degree of reaction con¬ 
clusions as to the development of the disease must be drawn with 
great care. The reported failures to discover the lesions of 
tuberculosis in making post-mortem examinations upon animals 
that have been condemned by the use of tuberculin, are incor¬ 
rect in great part, since practically all of the tuberculous animals 
killed in European countries are killed in slaughter-houses and 
their flesh is intended for the market after inspection and under 
certain restrictions and exceptions, so it is quite evident that all 
parts cannot be fully investigated and doubt always accompanies 
a negative result. 
Professor Bang’s personal experience, which is larger than 
that of any other veterinarian, has shown but three cases of 
typical reaction in which it was not possible for him to discover 
tuberculous deposits and in one of these there was disease of a 
chronic and incurable character. It is stated, and this is well 
known to everyone who has used tuberculin practically, that 
some severe cases do not respond to the test and must be detected 
by a physical examination, and Professor Bang says that it is 
probably always possible to discover these cases by the usual 
clinical investigation, excepting where the disease has become’ 
stationary and is of slight development. These exceptions are 
minor and unimportant. Tuberculin is not to be relied upon 
implicitly as a diagnostic agent, but furnishes a method of diag¬ 
nosis so incomparably superior to the methods previously em¬ 
ployed that it is scarcely to be compared with them. 
