122 BACTERIAL POISONS. 



BAUMGARTEN draws the following conclusions from his 

 experiments with tuberculin on rabbits with inoculation 

 tuberculosis : 



It causes an exudative inflammation in the vascular 

 tissue about the tubercle, and in this way the tuberculous 

 tissue may be isolated and, when situated superficially, re- 

 moved. In some cases, however, after the prolonged employ- 

 ment of the agent, the tuberculous tissue itself may, under 

 the influence of the exudative fluid and the polynuclear 

 leucocytes, break down and form abscesses. The bacilli 

 themselves are in no way harmed by the use of tuber- 

 culin, and, after its constant employment for months, they 

 retain their original form and lose none of their virulence. 

 Some preparations seem to show that the bacilli multiply 

 more rapidly when the injections are made, but a positive 

 statement on this point is reserved until further studies 

 have been made. It is certain, however, that the non- 

 tubercular tissue of animals acquires no immunity against 

 the disease from the injections. This is shown by the 

 appearance of metastatic foci in animals in which from 

 seven to twelve grammes of the original lymph (an amount 

 which would be equivalent to from seventy to one hundred 

 and eighty grammes in man) has been injected. It is further 

 shown by the fact that in some animals treated subcutane- 

 ously, tubercles have appeared at the point of injection. 



PRUDDEN and HODENPYL, summarize the results which 

 they have obtained by the inoculation of animals with dead 

 tubercle bacilli as follows : " These dead tubercle bacilli 

 are markedly chemotactic. When introduced in consider- 

 able amount into the subcutaneous tissue or into the pleural 

 or abdominal cavities, they are distinctly pyogenetic, caus- 

 ing aseptic localized suppuration. Under these conditions 

 they are capable, moreover, of stimulating the tissues about 

 the suppurative foci to the development of a uew tissue, 

 closely resembling the diffuse tubercle tissue induced by 

 the living germ. We have found that dead tubercle bacilli 

 introduced in small numbers into the bloodvessels of the 

 rabbit largely disappear within a few hours or days, but 

 that scattering individuals and clusters may remain here 



