KOCH'S OLD TUBERCULIN. 261 



tubercle in which the bacilli had been killed by heat. It con- 

 tains the dead and often macerated bacilli, the substances in- 

 destructible by boiling which existed in these bacilli, non-volatile 

 products formed by them from the food material when alive, 

 and the concentrated remains of the bouillon and glycerin. The 

 injection of .25 c.c. of tuberculin into a healthy man causes, in 

 from three to four hours, malaise, tendency to cough, laboured 

 breathing, and moderate pyrexia; all of which pass off in twenty- 

 four hours. The injection (the site of the injection being quite 

 unimportant), however, of .01 c.c. into a tubercular person gives 

 rise to similar symptoms, but in a much more aggravated form, 

 and in addition there occurs around any tubercular focus great 

 inflammatory reaction, resulting in necrosis and a casting off 

 of the tubercular mass, when this is possible, as for instance 

 in the case of lupus. The bacilli are, it was shown, not killed 

 in the process. 



Koch's theory of the action of the substance was that the tubercle bacillus 

 ordinarily secretes a body having a necrotic action on the tissues. When this 

 is injected into a tubercular patient, the proportion present round a tubercular 

 focus is suddenly increased, inflammatory reaction takes place around, and 

 necrosis of the spreading margin occurs very rapidly, the material containing 

 the living or dead bacilli being thrown off en masse instead of being disin- 

 tegrated piecemeal. It appears, however, that this explanation may not be 

 the true one, for, on the one hand, other substances besides products of the 

 tubercle bacillus may 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 dis- 

 covery of tuberculin, Gamal^ia 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. 



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 it 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. 



