FERMKN'IATION. 557 



blood containing the rod-like organisms, in which, however, 

 the spores were not developed, he found the contagium to 

 be that which Dr. Sanderson calls " fugitive." It main- 

 tained its power of infection for five weeks at the furthest. 

 He then dried blood containing the fully-developed spores, 

 and exposed the substance to a variety of conditions. He 

 permitted the dried blood to assume the form of dust; 

 wetted this dust, allowed it to dry again, permitted it to 

 remain for an indefinite time in the midst of putrefying 

 matter, and subjected it to various other tests. After keeping 

 the spore-charged blood which had been treated in this 

 fashion for four years, he inoculated a number of mice 

 with it, and found its action as fatal as that of blood 

 fresh from the veins of an animal suffering from splenic 

 fever. There was no single escape from death after 

 inoculation by this deadly contagium. Uncounted millions 

 of these spores are developed in the body of every animal 

 which has died of splenic fever, and every spore of these 

 millions is competent to produce the disease. The name 

 of this formidable parasite is Bacillus anthracis.* 



Now the very first step toward the extirpation of these 

 contagia is the knowledge of their nature; and the knowl- 

 edge brought to us by Dr. Koch will render as certain the 

 stamping out of splenic fever as the stoppage of the plague 

 of pebrine by the researches of Pasteur. f One small item 

 of statistics will show what this implies. In the single 

 district of Novgorod in Russia, between the years 1867 and 

 1870, over fifty-six thousand cases of death by splenic 



* Kocb found that to produce its characteristic effects the contagium 

 of the splenic fever must enter the blood; the virulently infective 

 spleen of a diseased animal may be eaten with impunity by mice. 

 On the other hand, the disease refuses to be communicated by inocu 

 lation to dogs, partridges, or sparrows. In their blood Bacillus 

 anthracis ceases to act as a ferment. Pasteur announced more than 

 six years ago the propagation of the vibrios of the silk-worm disease 

 called flachcrie, both by fission and by spores. He also made some 

 remarkable experiments on the permanence of the contagium in the 

 form of spores. See " Etudes sur la Maladie des Vers a Soie ," pp. 

 168 and 256. 



f Surmising that the immunity enjoyed by birds might arise from 

 the heat of their blood, which destroyed the bacillus, Pasteur 

 lowered their temperature artificially, inoculated them, and killed 

 them. He also raised the temperature of guinea-pigs after inoculation, 

 and saved them. It is needless to dwell for a moment on the impor- 

 tance of this experiment. 



