TOXINS OF THE TUBERCLE BACILLUS 259 



give rise to similar effects in tubercular animals, and, on the other, a 

 similar reaction can take place in other diseases where there is locally in 

 the body a deposit of new tissue. Matthes has, for instance, found that 

 albumoses and peptones isolated from the ordinary peptic digestion of 

 various albumins give the same reaction in tubercular guinea-pigs. The 

 injection of milk, lactic acid, ricin, all give a similar result. Before the 

 discovery of tuberculin, Gamaleia had found that tubercular animals 

 were very susceptible to the toxins of the vibrio Metchnikovi ; and later 

 Metchnikoff found that a similar susceptibility existed towards the 

 toxins of the bacillus of fowl cholera. How complicated the tuberculin 

 reaction is is shown by the fact that a similar reaction has taken place 

 when tuberculin has been injected into persons suffering from diseases 

 other than tubercle, e.g. cancer, sarcoma, syphilis. 



The hopes which the introduction of tuberculin raised, that a 

 curative agent against tuberculosis had been discovered, were soon 

 found not to be justified. It was very difficult to see how the 

 necrosed material which was produced and which contained the 

 still living bacilli, could be got rid of either naturally, as would 

 be necessary in the case of a small tubercular deposit in a lung 

 or a lymphatic gland, or artificially, as in a complicated joint- 

 cavity where surgical interference could be undertaken. Not 

 only so, but the ulceration which might be the sequel of the 

 necrosis appeared to open a path for fresh infection. Soon facts 

 were reported which justified these criticisms. Cases where 

 rapid acute tubercular conditions ensued on the use of tuberculin 

 were reported, arid in a few months the treatment was practically 

 abandoned. 



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 : Tiie 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 tempera- 

 ture 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. 



While it is undoubted that tuberculin contains toxic products 

 formed by the bacilli, we know nothing of the nature of the 

 toxins present. From the fact that filtered cultures cause little 



