64 



THE AMEEICAN MONTHLY 



[April, 



organisms were present, the spores 

 are formed and sink to the bottom, 

 and inoculations produce the disease 

 for a long time afterward (at least 

 twelve weeks, as shown by experi- 

 ment). 



6. When substances containing the 

 Bacillus rods alone are somewhat di- 

 luted with distilled or well-water, the 

 development of. the rods is not 

 stopped ; but if the dilution is exces- 

 sive, the organism is soon destroyed, 

 and after thirty hours, inoculations fail 

 to produce the disease. That is, the 

 actively growing organism requires 

 a certain concentration of the nutri- 

 tive fluid in order to accomplish the 

 spore-formation. 



7. If flakes containing spores are 

 taken from a watch-glass (paragraph 

 5 above), containing putrid but still 

 virulent blood, and placed in a test- 

 tube full of distilled water, the viru- 

 lence is not destroyed, but is re- 

 tained for weeks unchanged. 



8. Such flakes may also be dried, 

 and after a certain time moistened 

 with water and again dried, and this 

 repeated indefinitely without de- 

 struction of the virulence. 



9. A watch-glass of fresh charbon 

 blood placed in a room at 8° (46.4° 

 F.) remains virulent for only three 

 days. The rods at this time have not 

 formed spores and show the granular, 

 disintegrating appearance which in- 

 dicates their death. 



Here, then, we have a series of 

 facts which show the connection 

 between the virulence of the blood 

 and the presence of the living Bacillus 

 anthracis. A single fact of this kind 

 might indeed be called a coincidence, 

 but even two such facts would, from 

 the nature of the case, afford a strong 

 probability of the virus being identical 

 with the organism ; but when it comes 

 to a set of nine facts, each of which 

 taken alone would be a remarkable 

 confirmation, it seems to me that, as 

 scientific men, we must accept them as 

 a demonstration. If 45° destroys the 

 virus before spores have formed, but 

 has no effect upon it afterwards ; if 



diluting the virus largely with 

 water destroys its power before 

 spores have formed, but has no effect 

 upon it afterwards ; if hermetical- 

 sealing destroys the virus before 

 spores have formed, but is without 

 effect after such spore-formation ; if 

 putrefaction destroys the virus when 

 there is not sufficient access of air for 

 the formation of spores, but has no 

 effect under opposite conditions ; if, 

 in short, the preservation of the virus 

 for any considerable time only occurs 

 when the conditions are such that 

 resting-spores form in the Bacillus 

 rods, then, I have no hesitation in 

 accepting it as a fixed fact that char- 

 bon is caused by the Bacillus anthra- 

 cis, and that the contagium, or virus, 

 consists of this alone. 



None of the later investigators, 

 so far as I am aware, have pub- 

 lished a single experiment to show 

 that the above facts, observed by 

 Koch,* were in any degree doubtful 

 or unreliable ; on the contrary, they 

 have been confirmed in a remarkable 

 manner by Cohn, Pasteur, Toussaint, 

 Greenfield, Buchner and others. 



In this article I have purposely 

 avoided any reference to those ob- 

 servations which, it is asserted, con- 

 flict with the conclusion that charbon 

 is caused by this bacterium. It is 

 simply my object, at present, to make 

 it clear that the organism and the 

 virus are one and the same thing, and 

 I believe that any unprejudiced sci- 

 entific man must accept this conclu- 

 sion as necessarily following from the 

 above facts. At another time I may 

 take up the observations which are 

 believed by some to conflict with this 



— An interesting article by Profes- 

 sor J. C. Arthur, on the trichomes of 

 Echinocystis lobata, with a plate, is 

 published in the Botanical Gazette for 

 March, 1881. 



* Dr. Koch, Die Aetiologie der Milzbrand- 

 Krankheit, begriindet auf die Entwicklungs- 

 geschichte des Bacillus Anthracis. Beitrdge 

 zur Biologie der PJiatizen, 3nd Band, 2nd 

 Heft. Breslau, 1876. 



