ANTHRAX. 28 1 



that at the end of three or four hours they had attained from 

 twenty to thirty times their original length, and at the end of 

 a few additional hours had formed filaments in many cases a 

 hundred times the length of the original rods ; and further, 

 it was seen that within the transparent rods little dots appeared ; 

 these hecame more and more distinct until the whole organism 

 was studded with minute ovoid bodies like peas within their 

 shell. After a time the integument fell to pieces, the place of 



o & &si '^!> 



c? ^ 

 Fig 13.— Spores. 



Fig. 12. — Spore-bearing- filaments. 



each rod being taken l^y a long row of seeds or spores. Koch 

 concluded that these spores, as distinguished from the rods, 

 constituted the contagium of the disease in its most deadly and 

 persistent form. 



By inoculating animals with the fresh blood of an animal 

 suffering from splenic fever, he found that they invarial^ly 

 died within twenty to thirty hours after inoculation. By 

 drying the infectious blood containing the rod-like organisms, 

 in which, however, the spores were not developed, he found the 

 contagion to be fugitive, maintaining its power of infection for 

 five weeks at the furthest. He then dried the blood containing 

 the fully developed spores, and exposed it to a variety of 

 conditions. He permitted the. dried l)lood to assume the form 

 of dust, wetted this dust, allowed it to dry again, placed it for 

 an indefinite period in the midst of putrefying matter, and 

 subjected it to other tests. After kee[ting this spore-charged 

 l;)lood, 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 drawn from the veins of an animal 

 suffering from splenic fever, each spore in the millions con- 



