84 



THE AMERICAN MONTHLY 



[May, 



Greenfield that, by his method of 

 cultivation, although the bacillus re- 

 tains its vitality and morphological 

 characteristics, it completely loses 

 the power of producing disease after 

 the twelfth generation. This fact we 

 are all willing to admit ; but it seems 

 absurd to bring it forward at this 

 late day, as some are doing, to show 

 that charbon is not due to this or- 

 ganism ; before Koch's observations 

 were made, it might have been ac- 

 cepted as having a bearing in that 

 direction, and would undoubtedly 

 have been a severe discouragement 

 to the followers of the germ-theory ; 

 but now, when the connection of the 

 bacillus with the disease is demons- 

 trated, it is useless to expect scientific 

 people to barter an established fact for 

 what is, at best, but a faint indication. 

 Nageli has long held the view 

 that the pathogenic bacteria are sim- 

 ply septic bacteria, which have been 

 acclimated in some way and thus 

 enabled to grow in the blood and 

 tissues of living animals.* This 

 opinion was the result of studies of the 

 septic forms, which he found could 

 be changed gradually from organisms 

 that produce one kind of fermenta- 

 tion to others that produce a fermen- 

 tation of an entirely different kind, and 

 they then almost lost the power to live 

 under the conditions which were at 

 first extremely favorable to them. 

 Acting upon this theory, Dr. Buchner 

 was able, by a series of very ingen- 

 ious experiments, carried out in 

 Nageli's laboratory, to confirm Green- 

 field's results and to transform the 

 Bacillus anthracis into the harmless 

 Bacillus subtilis or " hay bacillus ; " 

 he was also able to reverse this 

 process, and change the Bacillus sub- 

 tilis into the Bacillus anthracis with 

 all its virulence. f 



* C. V. Nageli. Die niederen Pilze in 

 ihren Beziehungen zu den Infections-krank- 

 heiten und der Gesundheitspflege. Miinchen, 

 1877. 



f Dr. Hans Buchner. Ueber die experi- 

 mentelle Erzeugung des Milzbrandcontagiums 

 aus den Heupilzen. Miinchen, 1880. 



4. Toussaint's experimemts. — In 

 his first communication, this gentle- 

 man stated that fresh anthrax blood 

 which had been heated to 55° (131° F.) 

 might be inoculated on susceptible 

 animals without causing disease, and 

 that it had the property, when so in- 

 oculated, of protecting such animals 

 from the effect of subsequent inocu- 

 lations with virulent blood. It was 

 believed that the bacilli were all 

 destroyed at this temperature, and 

 that the acquired immunity resulted 

 from the introduction of substances 

 which had been formed by them. 



In this a fact and a theory were 

 combined, and some of those who 

 are so fond of criticising the germ- 

 theory seemed unable to comprehend 

 where the one stopped and the other 

 began ; I think all were willing to 

 accept the former, but some of us 

 refused to believe the latter until 

 better evidence was furnished. This, 

 was fortunate, for when M. Toussaint 

 came to try his experiments on a 

 larger scale, he was obliged to recall 

 the theoretical part of his first state- 

 ment. Twenty sheep were inoculated 

 with the prepared virus at Alfort, of 

 which four died of charbon, while all 

 the remainder were sick of the same 

 disease, but recovered. The heat, 

 therefore, certainly reduced the ac- 

 tivity of the virus, and caused it to 

 produce a milder form of disease ; 

 but the immunity conferred was 

 demonstrated to be the result of this 

 mild form of the malady, and not 

 to the introduction of an inconsider- 

 able quantity of a chemical sub- 

 stance.* 



Pasteur's latest researches. — 

 Since the above was written, I have 

 received the Comptes Rendus de 

 r Academie des Sciences for February 

 28th, 1881, in which M. Pasteur 

 communicates his latest researches 

 in regard to the charbon virus. He 

 had previously discovered that the 

 action of atmospheric oxygen for a 

 number of months (five to eight), 



* Comptes Rendus, XCI, pp. 457-8. 



