25 o THE POPULAR SCIENCE MONTHLY. 



four years, and might be even pulverized into dust, without losing its 

 power of infection. 



Here I would stop to cite the prophetic words used by Professor 

 Tyndall, when giving an account to a Glasgow audience, in 1876, of 

 Koch's then recent researches : " The very first step toward the extir- 

 pation of those contagia is the knowledge of their nature ; and the 

 knowledge brought to us by Dr. Koch will render as certain the 

 stamping out of splenic fever as the stoppage of the plague of p'ebrine 

 by the researches of Pasteur." 



It was but fitting that the complete verification of this prediction 

 should be the direct result of the labors of the illustrious man on 

 whose previous work it was based, although others were at work, 

 more or less successfully, in the same direction. 



One of the first questions examined by Pasteur was the cause of 

 outbreaks of " charbon " in its most deadly form among flocks of 

 sheep feeding in what appeared to be the healthiest pastures, far re- 

 moved from any obvious source of infection. Learning by the inqui- 

 ries he instituted that special localities seemed haunted, at distant 

 intervals, by this plague, he inquired what had been done with the 

 bodies of the animals that had died of it, and learned that it had been 

 customary to bury them deep in the soil, and that such interments had 

 been made, it might have been ten years before, beneath the surface 

 of some of the very pastures in which the fresh outbreaks took place. 

 Notwithstanding that the depth (ten or twelve feet) at which the car- 

 casses had been buried seemed to preclude the idea of the upward 

 traveling of the poison-germs, the divining mind of Pasteur found in 

 earth-worms a probable means of their conveyance, and he soon ob- 

 tained an experimental verification of his idea, which satisfied even 

 those who were at first disposed to ridicule it. Collecting a number 

 of worms from these pastures, he made an extract of the contents of 

 their alimentary canals, and found that the inoculation of rabbits and 

 Guinea-pigs with this extract gave them the severest form of " char- 

 bon," due to the multiplication in their circulating current of the 

 deadly anthrax-bacillus, with which their blood was found after death 

 to be loaded. 



Another mode in which the disease-germs of anthrax may be con- 

 veyed to herds of cattle widely separated from, each other and from 

 any ostensible source of infection was discovered by the inquiries 

 prosecuted, a few years ago, by Professor Burdon-Sanderson at the 

 Brown Institution, in consequence of a number of simultaneous out- 

 breaks which occurred in different parts of the couutry. It was found 

 that all the herds affected had been fed with brewers' grains supplied 

 from a common source ; and, on examining microscopically a sample 

 of these grains, they were seen to be swarming with the deadly bacil- 

 lus, which, when it has once found its way among them, grows and 

 multiplies with extraordinary rapidity. 



