CHANGES m THE BLOOD. 109 



interior, and it is often found tliat there is hardly a single white 

 corpuscle in the interior of which bacilli cannot be seen. 



Disease induced by the inoculation of the blood of septicsemic 

 mice cannot so successfully be induced in so many different 

 animals as with that of anthrax. Thus Koch failed to cause 

 it by inoculating rabbits, and even field mice resisted the 

 inoculations. 



Occurring along with the septicsemic bacillus, Koch has found 

 in mice, after the introduction of putrefying blood, a micrococcus 

 in the neighbourhood of the place of injection. This organism 

 is of rapid growth, and forms very regular chains. As a rule, 

 when an animal dies of septicaemia after about two days, none 

 of the numerous forms of bacteria which were injected with the 

 putrid blood can be discovered, except the septicsemic bacilli, 

 or it may be a few residual specimens growing with difficulty. 

 It must therefore be supposed that none of the other bacteria 

 injected at the same time find in the body of the living mouse 

 a suitable soil, and that they therefore die more or less quickly. 

 Koch's attention was therefore arrested when he found in some 

 cases, growing at and about the inoculated spot, micrococci in 

 unusual abundance and of a constantly characteristic form- 

 They were not present in the blood, and by inoculation with 

 the blood the septicsemic bacilli alone were transmitted. In 

 order to test whether they could be inoculated, it was necessary 

 that the material should be taken from the place of injection- 

 Inoculations carried out in this way were successful in pro- 

 ducing both forms of disease, and the virulence of the serum 

 from the subcutaneous cellular tissue containing these micro- 

 cocci was just as marked as that of the septicsemic blood. 

 When the point of a knife which had been well cleaned was 

 merely brought in contact with the subcutaneous tissue at a 

 spot about one centimetre and a half from the place of injection 

 or inoculation, and when with this knife another animal was 

 immediately inoculated, the inoculation was successful on every 

 occasion. Septicsemia was of course always produced at the 

 same time, because the serum used contained also septicsemic 

 bacilli. The influence of these micrococci on animal tissues, 

 and their mode of spreading, can be best traced on the ear of a 

 mouse, and it is specially instructive to compare an ear on 

 which only septicsemic bacilli have been inoculated with one 



