LEPROSY. 335 



making the puncture. The writer's own experi- 

 ments have since shown that this precaution is 

 probably inadequate ; for the micrococcus of pus 

 is not killed by exposure for two hours to 25 per 

 cent alcohol. 



Up to the present time, the supposition that the 

 bacillus of Hansen bears a causal relation to lep- 

 rosy depends for its support entirely upon the fact 

 that it is found in the leprous tubercles, etc. It 

 is not well established that these bacilli have dis- 

 tinctive morphological characters and staining re- 

 actions. Indeed, Koch finds that they closely 

 resemble his bacillus of tuberculosis in both these 

 particulars. But even if this bacillus were proved 

 to be peculiar to leprosy, in the absence of suc- 

 cessful inoculations with pure cultures its causal 

 relation to the disease must remain in question; 

 for, in view of what we know of the habits of the 

 bacteria generally, there is nothing improbable 

 in the supposition that this particular species is 

 able to invade tissues of a low grade of vitality, 

 and finds in the leprous tubercles the pabulum 

 necessary for its development. If, however, lep- 

 rosy is truly an infectious disease, which seems to 

 be a matter of considerable doubt, the rapidly 

 accumulating evidence in favor of the parasitic- 

 germ theory, in explanation of the etiology of 

 these diseases, lends strong probability to the 

 first-mentioned hypothesis. 



Hansen has endeavored to inoculate rabbits with 

 leprosy, by introducing portions of the leprous 



