206 TECHNOLOGY OF BACTERIA. 



" First. A single disease-germ cannot produce this 

 extremely virulent disease ; it cannot even multiply 

 sufficiently to produce the local irritation at the point 

 of inoculation. When a quantity of virus was intro- 

 duced into the tissues, which should have contained at 

 least twelve germs, there was no effect, either general 

 or local ; but by increasing this one third, with the same 

 birds, the local irritation appeared. 



" Second. It is apparent that the local resistance to 

 the germs fails, while the constitutional resistance may 

 still be perfect, and that in this case there may be a 

 local multiplication of the organisms for two or three 

 weeks without any disturbance of the general health. 



" Third. That this local multiplication of the virus 

 is sufficient to grant a very complete immunity from the 

 effects of such virus in the future." 1 



Method by Intravenous Injection. In sympto- 

 matic anthrax, it has been found by Arloing, 

 Cornevin, and Thomas, that intravenous injection 

 of the virus produces in the calf, the sheep, and the 

 goat only a slight indisposition, lasting for two or 

 three days; and that subsequently the tumors 

 characteristic of this disease are not developed as 

 the result of inoculation in the muscles with the 

 bacterium to which the disease is ascribed. 



Attenuation of Virus ly Chemical Reagents. The 

 attenuation of virulence which results from ex- 

 posure to oxygen (method of Pasteur), or to an 

 elevated temperature (method of Toussaint), seems 

 to depend upon diminished reproductive activity 



i The Med. Record, April 7, 1833, p. 371. 



