IMMUNITY PHENOMENA IN TUBERCULOSIS 299 



tuberculin reaction on the one hand, and the cutaneous and 

 ophthalmic reactions on the other, are analagous. In the former 

 there is the occurrence of local inflammation with metabolic 

 changes and fever ; in the latter, of mild inflammatory effects, 

 in both cases the phenomena being found only in tubercular 

 subjects. 



The Use of Old Tuberculin in the Diagnosis of Tuberculosis in Cattle. 

 In cattle, tuberculosis may be present without giving rise to apparent 

 symptoms. It is thus important from the point of view of human 

 infection that an early diagnosis should be made. The method is 

 applied as follows : The animals are kept twenty-four hours in their 

 stalls, and the temperature is taken every three hours, from four hours 

 before the injection till twenty-four after. The average temperature in 

 cattle is 102 '2 F. ; 30 to 40 centigrammes of tuberculin are injected, and 

 if the animal be tubercular the temperature rises 2 or 3 F. in eight to 

 twelve hours, and continues elevated for ten to twelve hours. Bang, who 

 has worked most at the subject, lays down the principle that the more 

 nearly the temperature approaches 104 F. the more reason for suspicion 

 is there. He gives a record of 280 cases where the value of the method 

 was tested by subsequent post-mortem examination. He found that with 

 proper precautions the error was only 3*3 per cent. The method has 

 been largely practised in all parts of the world, and is of great value. 



(2) Immunity Phenomena in Tuberculosis. Although 

 recovery from tuberculosis is of frequent occurrence in man, we 

 have at present no clear ida of the processes at work. The 

 object of the therapeutic application of the tuberculins introduced 

 by Koch was to increase the hypothetically existing powers of 

 resistance of the infected organism. The underlying principle 

 was thus the same as in immunisation procedures (e.g., against 

 the typhoid bacillus) with the difference that immunisation was 

 proceeding in an already infected animal. Such facts have 

 stimulated inquiries with a view to observing whether the sera 

 of persons suffering from tuberculosis possess the qualities found 

 in circumstances where it is known that immunisation is 

 occurring. 



(1) Immune-bodies and Precipitins. Evidence for the 

 existence of these in tuberculosis has been sought by applying 

 the method of complement fixation (see p. 131), e.g., the serum 

 of a tubercular animal being mixed with tuberculin, the mixture 

 is tested for its capacity of absorbing complement. Following 

 this line, Wassermann and others have found evidence of the 

 presence of an antituberculin in tubercular foci, and this is 

 taken as an indication of the occurrence of a vital reaction 

 against the poisons of an invading organism. Generally speak- 

 ing, such an antituberculin is absent from the blood serum of 

 most tubercular patients. In certain cases it may be present in 



