XII.] 



Anthrax. 139 



obtained by other methods than that of Pasteur and of the 

 possible return of virulence. 



If we proceed in the next place to enquire how the parasite 

 causes disease, we find that it is not possible to give a decisive 

 answer ; still there are some definite facts and analogies leading 

 to a conception of the matter which approaches very near to 

 probability. The first fact is the appearance of the carbuncle 

 of anthrax in human subjects infected by inoculation or 

 through a wound. At the spot where the infection has taken 

 place there appears at first a violent local inflammation of the 

 skin, and it is not till 2-3 days later that the general symptoms 

 supervene. The inflammation is specifically different from 

 other violent inflammations of the skin, just as the local symptoms 

 produced by a definite poison with peculiar effects differ from 

 others which are caused by some other poison or by other 

 causes. This, it appears to me, excludes the view sometimes 

 expressed, that the Bacillus becomes the exciting cause of 

 disease by giving rise to merely mechanical disturbances, or 

 simply by withdrawing the oxygen from the living blood in 

 which it vegetates ; it is much more probable that the effect of 

 the Bacillus is peculiar to itself, the result of a specific poison. 

 If this is conceded, then the poison must issue, be excreted 

 from the Bacillus, for it could have no effect if it remained in 

 it. This agrees with MetschnikofFs observation that the same 

 blood-cells readily absorb the Bacillus if it is not virulent, while 

 if it is virulent it is virtually not absorbed. There must be 

 something in the virulent Bacilli which there is not in the 

 others, and it is probable, as was shown above, that this some- 

 thing possesses distinct chemical properties, and it must be on 

 the outside of or at least at the surface of the body of the Bacillus, 

 for if it were only in the inside there would be no reaction 

 with the blood-cells upon their coming into contact with the 

 Bacillus. 



We know nothing of the real nature of the poison which is 

 thus supposed to be excreted by the Bacillus. Attempts to 



