610 PATHOGENIC MICROORGANISMS 



2. Make the injection at 10 P.M. 



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

 hours thereafter until 6 or 8 P.M. 



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

 from 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 c.c. Bulls and very 

 large animals may receive three c.c. The injection 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 frequent passage 

 of softened dung. There may also be slight acceleration of the pulse 

 and of breathing. 



The febrile reaction in tuberculous cattle 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 injec- 

 tion 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 

 therapeutically, by Koch, 63 shortly after its discovery. Hailed with 

 the most optimistic enthusiasm, its possibilities were overestimated and 

 hopeless cases were treated unskillfully, with unsuitable dosage. The 

 consequence was that harm was done, the method was attacked by 

 Virchow and others and the new therapy fell into almost complete 

 neglect. At present, the use of tuberculin has again been revived, but 

 with greater caution and with a thorough understanding of its limitations. 

 The tendency has been toward smaller dosage and the limitation of the 



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



