EELATION OF PATHOGENIC TO SEPTIC BACTERIA. 49 



inoculation with infinitesimal doses of artificially cultivated 

 Bacillus anthracis. The presence of spores makes no 

 difference to the rapidity of death. A guinea-pig inoculated 

 with spores that had been first of all frozen with ether spray 

 and then allowed to thaw died within twenty-four hours. 



Observations on Inoculation. 



It is not necessary for me to enter here into a description of 

 the symptoms of anthrax in rodents, since these are well known 

 through the various descriptions already existing, and I may 

 refer the reader especially to those given by Koch in his several 

 writings on anthrax. 



But one fact I must mention here, viz. the great irregularity 

 presented by the spleen in the animals (mice, guinea-pigs, and 

 rabbits). In some instances the spleen is very much enlarged, 

 in others it is not enlarged at all, but in all instances it con- 

 tains bacilli, though the number of these varies considerably 

 without, however, standing in any relation to the duration of 

 the illness. 



1. Inoculation with blood of an animal dead of anthrax : 



The blood was derived from the heart of mouse, guinea-pig, 

 or rabbit, either quite fresh or after one, two, three, to eight 

 days. In all instances death followed after the introduction of 

 infinitesimal doses. Before inoculation I ascertained that the 

 blood contained the bacilli in sufficient numbers to make it pretty 

 certain that some bacilli will be present even in so minute a 

 quantity. When using infinitesimal doses it is necessary to 

 bear this in mind for the following reasons : — Supposing the 

 point of a needle is well steeped into the blood of a guinea-pig 

 or rabbit dead of anthrax, and then with this needle the skin 

 of a mouse, or guinea-pig, or rabbit is pricked down to the sub- 

 cutaneous tissue, out of ten such inoculations the chances are 

 that all ten will be successful ; but supposing the point of the 

 needle be well dipped into the blood of a mouse dead of anthrax 

 for some hours, and the inoculation be performed as above, out 

 of ten such inoculations the chances are that there will be 



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