VACCINES : DIAGNOSTIC AND CURATIVE 107 



remove the bacilli, and the filtrate evaporated to one- 

 tenth its original volume. Before it is sold to be used 

 by veterinary surgeons it is diluted with nine times 

 its volume of a weak solution of carbolic acid in lo per 

 cent, glycerine. The dose of the diluted vaccine for 

 an adult bovine is usually about 3 to 4 c.c. when 

 given as a subcutaneous injection under the skin of 

 the neck or behind the shoulder. If the vaccine is 

 prepared so that its strength differs from that given 

 above, then the dose will vary accordingly. The 

 temperature of the animal to be tested is taken for 

 one or two days, and if found to be within normal 

 limits, the injection is then given. The temperature is 

 noted at the time of injection, and also at the ninth, 

 twelfth, fifteenth, and eighteenth hours following the 

 inoculation. In an animal in which the temperature at 

 the time of inoculation was not above 103° F., a rise of 

 temperature to 104° F. or over is considered as a posi- 

 tive reaction — i.e., the animal is tubercular. If the 

 initial temperature is above 103° F., the test should be 

 postponed for a few days. With this test the tempera- 

 ture frequently rises to 105° or 106° F., and in such 

 cases the animal shows signs of fever, loss of appetite, 

 etc. In experienced hands the proportion of errors is 

 exceedingly small, although in very advanced cases a 

 negative result is not uncommonly obtained. 



There are several modifications of the tuberculin 

 test. 



The ophthalmic test is performed either with Cal- 

 mette's tuberculin or with a i per cent, solution of 

 Koch's Old Tuberculin. Calmette's preparation consists 

 of an alcoholic precipipate of tuberculin to which no 

 preservative has been added. Wolff-Eisner gives the 

 following description of the method of preparation : A 

 glycerine-broth culture of the bovine tubercle bacillus, 



