DIAGNOSIS OF TUBERCULOSIS 497 
Immunity. — Cattle and swine exhibit little or no natural immunity 
to infection with the bovine tubercle bacillus. The most satisfactory 
prophylaxis consists in isolating infected animals from the herd, 
disinfection of the stables and testing all apparently sound animals 
with tul)erculin. 
Tuberculin Test. —The preparation of bovine tuberculin is precisely 
similar to that of human tuberculin, except that the bovine organism 
is used. The test is carried out in the following manner: 
The temperature of the animal is taken at frequent intervals for 
twenty-four hours, then tuberculin is injected subcutaneously, prefer- 
ably over the fore-shoulder, about 10.00 p.m. Temperatures are taken 
from 6.00 a.m. of the following morning at two-hour interals until 
10 P.M. An elevation of temperature of from 1° to 3° F. occurs within 
a few hours in positive cases and a hot swollen area of induration 
appears around the site of inoculation. Both the febrile reaction and 
the indurated area slowly become normal. The International Com- 
mission on the Control of Bovine Tuberculosis^ states: 
"1. That tuberculin, properly used, is an accurate and reliable 
diagnostic agent for the detection of active tuberculosis. 
"2. That tuberculin may not produce a reaction under the following 
conditions: 
(a) When the disease is in the period of incubation. 
(b) When the progress of the disease is arrested. 
(c) When the disease is extensively generalized. 
The last condition is relatively rare and may usually be detected 
by physical examination. 
"3. On account of the period of incubation and the fact that arrested 
cases may sooner or later becorne active, all exposed animals should 
be retested at intervals of six months to one year. 
"4. That the tuberculin test should not be applied to any animal 
having a temperature higher than normal. 
"5. That an animal having given one distinct reaction to tuberculin 
should thereafter be regarded as tuberculous. 
"6. That the subcutaneous injection of tuberculin is the only method 
of using tuberculin for the detection of tuberculosis in cattle, which 
can be recommended at the present time. 
"7. That tuberculin has no injurious effect upon healthy cattle." 
Avian Tubercle Bacillus.-— Hens, pheasants and other birds are 
su})ject to a spontaneous disease which is anatomically very much 
like tuberculosis of other warm-blooded animals. Koch^ believed 
that the organism of avian tuberculosis was identical with the bovine 
tubercle bacillus, but later work has not confirmed this assertion. 
1 Forty-seventh Annual Report of the American Veterinary Medical Association, 
September, 1910. 
'^ An excellent summary of the subject of avian tuberculosis is by Van Es and Schalk 
(North Dakota Agricultural Station Bull. 108, 1914). See also Weber and Bofinger: 
Die Hiihner-tuberkulose, Tub. Arb. a. d. kais. Gesundhamt, 1904, 1, 95. 
3 Mitt. a. d. Kais. Ges. Amt«, 1884, 2, 4. 
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