TUBERCULOSIS. 83 



increased frequency of respiration (to 180 per minute ?) and an ele- 

 vation of temperature of from 0.5° to 1°. Marked protnmo buUd 

 was a constant symptom and the pupils were dilated. From two to 

 three eg. sufficed to kill rabbits, death occurring in from two to four 

 days. The place of injection was found to be reddened and hemor- 

 rhagic spots were obsei-ved in the mucous membrane of the stomach 

 and small intestines. Occasionally considerable amounts of clear 

 fluid were found in the peritoneal cavity. As early as 1888, Ham- 

 merschlag had ascertained that cultures of the tubercle bacillus are 

 toxic to certain animals. Subsequently he reported that almost 27 

 per cent, of the cellular substance of the bacillus tuberculosis is solu- 

 ble in alcohol and ether. In this extract, he found, in addition to 

 fat and lecithin, a poison which induced in rabbits and guinea-pigs 

 convulsions followed by death. The part of the germ insoluble in 

 alcohol and ether was found to consist of cellulose and proteids. 

 Weyl obtained by macerating the bacillus in dilute soda solution an 

 extract which, when injected into animals, caused local necrosis. 

 Prudden and Hodenpyl summarized the results which they obtained 

 by the inoculation of animals with dead tubercle bacilli, as follows i 

 " These dead tubercle bacilli are markedly chemotactic. When in- 

 troduced in considerable amount into the subcutaneous tissue or into 

 the pleural or abdominal cavities, they are distinctly pyogenetic, 

 causing aseptic, localized suppuration. Under these conditions they 

 are capable, moreover, of stimulating the tissues about the suppurative 

 foci to the development of a new 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 blood 

 vessels of the rabbit largely disappear within a few hours or days, 

 but that scattering individuals and clusters may remain here and 

 there in the lungs and liver, clinging to the vessel walls for many 

 days without inducing any marked changes in the latter. After a 

 time, however — earliest in the lungs, later, as a rule, in the liver — 

 a cell proliferation occurs, in the vicinity of these dead germs, which 

 leads to the formation of new, multiple, nodular structures, bearing 

 a striking morphological resemblance to miliary tubercles. There is 

 in them, however, no tendency to cheesy degeneration and no evi- 

 dence of proliferation of the bacilli, but rather a steady diminution 

 in their number. It seems to us that the new structures regenerate 

 in a proliferation of the vascular endothelium under the stimulus of 

 the dead and disintegrating germs." Babes and Broca showed that 

 the introduction of dead tubercle bacilli into the bodies of animals 

 rendered them susceptible to the action of tuberculin, and the re- 

 action was most marked when the tuberculin had not been extracted 

 from the bacilli. They also claimed that the local changes induced 

 by the injection of dead bacilli were improved and could be healed 

 by injections of tuberculin ; but that under the influence of the tuber- 



