258 GENERAL THERAPEUTICS FOR VETERINARIANS 



without effect (contrary to anthrax). The moculated animals die 

 in 8 to 14 hours with sjonptoms of an extensive subcutaneous 

 cedema, in which the characteristic bacilli are easily demonstrated. 

 Guinea-pigs are also inoculated subcutaneously for black leg. 



Tuberculin Injection. — Tuberculin is obtained by the evapora- 

 tion of bouillon cultures of tubercle bacilli and is official [in Ger- 

 many] in two forms: as fluid (old tuberculin) and as dried tuber- 

 culin (dry tuberculin, tuberculol). [In the United States, the 

 evaporated tuberculin is diluted with a ]/2 P^r cent, solution of 

 carbolic acid before it is sent out to the practitioner, the extent 

 of the dilution varying in different laboratories.] Tuberculous 

 animals are very sensitive to tuberculin and react to it with fever 

 and local inflanunation. This reaction mdicates the presence of 

 tuberculosis; not with certainty, it is true, but yet with great 

 probability. Therefore, tuberculin is, after all, a very valuable 

 diagnostic agent. It is employed according to different methods: 



1. Subcutaneous (thermal reaction). 



2. Conjunctival (ophthalmic reaction, eye test). 



3. Cutaneous and intracutaneous (dermal reaction). 



1. The Subcutaneous Tuberculin Test (thermal reaction) 

 is the oldest method. Fluid tuberculin diluted [in Germany] 

 with ten times the amount of H per cent, carbolic acid solution 

 is injected under the skin. The dose of the tuberculin for cows 

 is 0.5 gram, for calves 0.1 gram. [The dose of the preparations of 

 tuberculin used in the United States varies from 1 c.c. to 4 c.c, 

 depending upon the extent to which the evaporated tuberculin has 

 been diluted with the J^ per cent, carbolic acid solution.] The 

 diagnostic reaction consists of a rise of temperature of at least 

 2* F., which occurs 12 to 15 hours after the injection. [It is very 

 generally agreed that a reaction may occur or begin at any 

 time from the 9th to the 20th hour after injection, and it is 

 therefore considered necessary to begin the temperature measure- 

 ments not later than the 9th hour and to continue them in all 

 cases until at least the 20th hour after the tuberculin is injected. 

 In any case in which the temperature is rising at the 20th hour, 



