214 TEXT-BOOK OF BACTERIOLOGY. 



Now we are aware that the anthrax bacilli cannot pass beyond 

 the stomach of a healthy animal, being killed by the gastric juice, 

 and that only the spores are able to get as far as the intestines. 

 It will be asked: How do the animals get these spores, and how 

 are these facts to be reconciled with the peculiar epidemic nature 

 of the disease ? 



Long before the anthrax bacillus was known or even dreamed 

 of, people had noticed that the place where an animal had died of 

 anthrax, or where a victim of that disease had been buried, re- 

 mained a dangerous pasture for sheep and cattle. Very often the 

 terrible scourge broke out again at such a place, and people learned 

 to avoid it without knowing exactly why. 



When at length the bacillus was discovered, one endeavored to 

 explain these facts in connection with it, and a very plausible ex- 

 planation was soon found. In the buried victim, it was said, the 

 bacilli continued to develop and increase, and only required to reach 

 the surface in order to infect any animal that might be there. For 

 this somewhat difficult resurrection from the grave, ways and 

 means were quickly advanced. Either, as Pasteur maintained, the 

 earth-worms aided the micro-organisms, loading themselves deep 

 below with crumbs of earth containing bacilli, and delivering them 

 safe at the surface, or the underground water, that " deus ex mas- 

 china " for all who search causes for diseases in the lap of mother 

 earth, somehow or other managed to convey the anthrax bacteria 

 to the surface, and the varied conditions of the soil as to warmth 

 and temperature had to appear as witnesses of the process. 



For the latter assertion not a shadow of a proof could be ad- 

 duced, and the earth-worm theory was disproved experimentally 

 by Koch, who showed that the entire supposition to support which 

 these explanations have been conjured up was without foundation- 



The preservation and distribution of the virus — i.e., the forma- 

 tion of spores — does not take place underground. The bacilli (the 

 sporeless rod-cells) soon perish at a depth of two or three metres 

 (as may be proved by direct experiment), because even during the 

 warm season the low temperature which prevails at that depth 

 does not allow of any growth, still less of any sporulation, for which, 

 as we know, a pretty high temperature, about 24° C, is requisite. 



This temperature, however, is not attained at the depth of half 

 a metre in our climate, and another requisite, the free access to 

 oxygen, is also difficult, to say the least, at such a depth below the 

 surface. 



Everything, indeed, leads us to the conviction that the devel- 

 opment of anthrax spores — i.e., of the only form of anthrax poison 



