ANTITUBERCULAR SERUM. 253 



present in a growing culture, is unantagonised and now gives 

 the usual reaction. It is thus probable that more than one 

 toxic body may be formed by the tubercle bacillus. 



The Use of Tuberculin in the Diagnosis of Tuberculosis 

 in Cattle. This is now the chief use to which tuberculin 

 is put. 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 

 byres 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 centi- 

 grammes 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 1 04 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 is largely practised on the Continent, and ought to 

 be more widely applied. 



Immunisation against the Tubercle Bacillus : Anti- 

 tubercular Serum. Tuberculosis differs from other diseases 

 against which animals can be immunised in that there is 

 no evidence that one attack protects against a second. 

 Further, we have no means of obtaining truly attenuated 

 tubercle bacilli. Many attempts at immunisation have, 

 however, been made. It has been thought by some that 

 the tubercle bacilli from so-called scrofulous glands are less 

 virulent than those say from phthisis, but apparently here 

 sufficient attention has not been paid to the difference of 

 the numbers of bacilli injected in each case, and this 

 appears to be a very important point. Experiments have 

 also been brought forward which appear to show that the 

 injection of bacilli from avian tuberculosis could protect the 



