New York AGRICULTURAL EXPERIMENT STATION, 35 
TUBERCULIN. 
Tuberculin is the concentrated liquid, usually glycerinated bouil- 
lon, on which the tubercle bacteria have grown until the products 
resulting from their multiplication have become imparted to the 
medium in sufficient quantity to inhibit their further development. 
It is not definitely determined just what these products are or just 
how they are elaborated. 
In the preparation of tuberculin the saturated cultures are heated 
to destroy the tubercle bacteria, filtered through the Pasteur or 
Berkefelt filter to remove all the bacteria, and the filtrate condensed 
over a water bath. To the properly concentrated fluid a little car- 
bolic acid is added to preserve it. It is evident, therefore, that 
tuberculin cannot produce tuberculosis, as the tubercle bacteria have 
been first killed by heat and then removed by filtration. It has never 
been known to produce any bad effect upon either tubercular cattle 
or healthly ones. It is the most accurate test for the detection of 
disease that is known to medical science. 
Pe Pele rlONtOr LUBERCULIN: 
In applying the tuberculin it is important to observe the following: 
1. The normal temperature of the animal to be tested must be 
determined. It is recommended that it be taken hourly or every 
two hours for the day proceeding the test. In practice veterin- 
arians usually take the temperature but once or twice before in- 
jecting the tubeculin. 
2. The tuberculin is injected subcutaneously in the side of the 
neck. Care should be taken that the syringe is sterile and the site 
of injection should be disinfected. The size of the dose depends 
upon the preparation of the tuberculin, that is, the degree of its 
concentration. 
3. Beginning 6 or 8 hours after injection the temperature should 
be taken hourly, or at least every two hours for fully three-fourths 
of a day. 
4. During the time of testing the cattle should be kept quiet and 
free from all exposures and fed normally. 
5. In case of reaction there should be a rise of at least 1.5° F. 
above the normal individual temperature as determined on the pre- 
