49G PATHOGENIC MICROORGANISMS 



time required by the above directions, the following shortened course is 

 recommended : 



1. Begin to take the temperature at 8 A.M., and continue every 2 

 hours until 10 P.M. (omitting at 8 P.M., if more convenient) ; or take the 

 temperature at 8 A.M., 12 M., and 10 P.M. 



2. Make the injection at 10 P.M. 



3. Take the temperature next morning at 6 or 8 A.M., and every 2 

 hours thereafter until 6 or 8 P.M. 



Each adult animal should receive 2 c.c. of the tuberculin as it is sent 

 frem the laboratory. (The tuberculin sent out from the central labora- 

 tory at Washington is already diluted; 2 c.c. represents 0.25 c.c. of the 

 concentrated "Old Tuberculin" of Koch.) Yearlings and two-year-olds, 

 according to size, should receive from 1 to 1.5 cubic centimeters. Bulls 

 and very large animals may receive three cubic centimeters. The injec- 

 tion should be made beneath the skin of the neck or shoulders behind 

 the scapula, after washing the area with a weak carbolic acid solution. 

 There is usually no marked local swelling at the seat of the injection. 

 There are now and then uneasiness, trembling, and the more fre- 

 quent passage of softened dung. There may also be slight acceleration 

 of the pulse and of the breathing. 



The febrile reaction in tuberculous eattle following the subcutaneous 

 injection of tuberculin begins from six to ten hours after the injection, 

 reaches the maximum nine to fifteen hours after the injection, and 

 returns to normal eighteen to twenty-six hours after the injection. 



A rise of two or more degrees Fahrenheit above the maximum tem- 

 perature observed on the previous day should be regarded as an indica- 

 tion of tuberculosis. For any rise less than this a repetition of the 

 injection after four or six weeks is highly desirable. 



It is hardly necessary to suggest that for the convenience of the one 

 making the test the animals should not be turned out, but fed and 

 watered in the stable. It is desirable to make note of the time of feed- 

 ing and watering and of any temperature fall after watering. 



The tuberculin should not be used later than six weeks after the 

 date on the bottle, nor if there is a decided clouding of the solution. 



Therapeutic Uses of Tuberculin. Tuberculin was first used therapeu- 

 tically, shortly after its discovery, by Koch. 1 Hailed with the most 

 optimistic enthusiasm, its possibilities were overestimated and hope- 

 less cases were treated unskilfully, with unsuitable dosage. The conse- 

 quence was that harm was done, the method was attacked by Virchow 

 1 Koch, Deut. med. Woch., iii, 1891. 



