28 



should be postponed until the temperature has returned to its 

 normal This varies in different animals within comparatively 

 narrow limits under varying conditions, but should never as a rule 

 be above 102° or 102.5° F. 



Having obtained the normal temperature of the animal, the 

 tuberculin should be prepared for use. When it is purchased in 

 the concentrated form it should be diluted, one part of tuberculin 

 being added to nine paTts of a 1 per cent solution of carbolic acid, 

 prepared with distilled water. By some manufacturers it is di- 

 luted before being sold ; in such cases it is to be used in the form 

 in which it is purchased. 



To prepare the animal for the injection of the tuberculin, the 

 hair should be clipped from a part of the skin as large as a silver 

 dollar, on the neck, brisket, on the part of the side just back of 

 the elbow or at a point just back of the scapula, midway between 

 the backbone and the point of the elbow. This area should then 

 be thoroughly cleansed with a 5 per cent solution of carbolic acid. 

 A strong hypodermic syringe, with a capacity of about 2^ cubic 

 centimeters, thoroughly cleaned by being filled and emptied sev- 

 eral times with a 5 per cent solution of carbolic acid or some other 

 equally good antiseptic, should be filled with the dilute solution of 

 tuberculin. A whole or a part of the contents of the syringe may 

 then be injected under the skin of that portion of the body previ- 

 ously prepared for its introduction. 



After removal of the needle, a few light strokes with the fingers 

 upon the part will serve to spread the fluid evenly about under the 

 skin. Care should be taken not to inject any air with the solu- 

 tion. This can be easily avoided by holding the syringe, after it 

 has been filled, needle end up, when the bubble of air will rise to 

 the top of the column of fluid and can then be forced out by pres- 

 sing upon the piston until the solution appears at the point of the 

 needle. 



The quantity of tuberculin to be used depends upon condition, 

 and varies from 1 to 3 cubic centimeters of the 10 per cent mixt- 

 ure. The dose for an average-sized cow is about 2.5 cubic centi- 

 meters, while 1 cubic centimeter would be sufficient for a 3'earling. 



If the animal is suspected of being tuberculous on account of 

 unthriftiness and emaciation, a comparatively large quantity' 

 should be used, as it has been found in many cases that animals 

 in the advanced stages of tuberculosis do not respond to the test 

 as readily as those in the early stages. 



It is best to administer the tuberculin during the latter part of 

 the day, when the temperature is normally highest. After it is 

 used the animal should be kept as quiet as possible in the stable 



