ANTISEPTIC SURGERY 16 



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phases of development and observed that in the 

 presence of oxygen, and at not too low a tempera- 

 ture, there appeared in the rod-like bacilli several 

 small round bodies or spores. These frequently 

 became liberated from their bacilli, and Koch 

 proved that they were very much more resistant 

 than the bacteria and were capable of producing 

 anthrax when inoculated into healthy mice. Koch 

 also succeeded in cultivating the bacilli of anthrax 

 in blood serum and aqueous humor by inoculating 

 one drop with a minute amount of material taken 

 from another drop* After making eight successive 

 transfers in this way, the bacteria multiplying in 

 the meantime, he found that the cultures would 

 convey the disease to new animals. 



These experiments of Koch resolved some of the 

 difficulties that had troubled Davaine. The per- 

 sistence of anthrax germs ; despite the fact that the 

 bacilli disappear soon after death, was shown to be 

 explicable through the vitality of the spores; and 

 the fact that the blood of animals dying of anthrax 

 is sometimes infectious and sometimes not, was 

 very readily accounted for as due to the circum- 

 stance that the spores appear or fail to appear 

 owing to varied conditions of temperature and the 

 supply of oxygen. 



