VACCINATION. IMMUNIZATION. INOCULATION 259 



the temperature measurements should be continued until the 

 temperature begins to fall or until a reaction occurs. American 

 veterinary sanitary authorities recommend that at least three 

 temperature measurements be taken before the tuberculin is 

 injected, at intervals of 2 or 3 hours, and that the tuberculin be 

 injected preferably between 6 and 9 p.m.] The disadvantages of 

 the subcutaneous method are that it is misleading in 13 per cent, 

 of the cases tested (incorrect diagnosis); that it requires a great 

 amount of time, as at least two temperature measurements must 

 be taken before and four after the injection; that it cannot be 

 applied to animals in a febrile condition; that cattle previously 

 injected with tuberculin will not react to the usual dose but require 

 five times the quantity; that the general condition and the milk 

 secretion is influenced unfavorably by the reaction fever, and 

 that now and then chronic tuberculosis is transformed into the 

 acute form. [According to American statistics, errors in diag- 

 nosis are much fewer than are indicated by the German figures 

 given above. Statistics compiled by the Bureau of Animal 

 Industry 2 show that of 24,784 cattle which reacted to tuberculin 

 from 1893 to 1908, 24,387 were found to be tuberculous on post- 

 mortem, which is only 1.07 per cent, failures.] 



2. The Ophthalmic Test (ophthalmic reaction, conjunctival 

 reaction) has been recently given the preference [in Germany] 

 over the subcutaneous method on account of its greater certainty, 

 simplicity, cheapness, and harmlessness, and also because it is not 

 influenced by the presence of fever or by a previous subcutaneous 

 injection. It is applied in the following manner: four drops of a 

 5 per cent, solution of dry tuberculin or of a 25 per cent, solution 

 of tuberculol are introduced into the conjunctival sac, or a quantity 

 of a 1 to 2 per cent, tuberculin vaseline the size of a pea is placed 

 in the conjunctival sac with a glass rod. A typical purulent dis- 

 charge from the eye and a pronounced oedema appear in 12 to 

 14 hours. Rectal, vaginal, and nasal applications have the same 

 effect. [In Pennsylvania, an alcoholic precipitate of a glycerin 



■ Twenty-fifth Annual Report, Bureau of Animal Industry, p. 99. 



