592 APPLICATION OF METHODS OF BACTERIOLOGY 



Pathogenesis. — The animals known to be susceptible to 

 inoculation with this organism are man, horses, calves, 

 dogs, goats, sheep, pigs, chickens, pigeons, rabbits, guinea- 

 pigs, and mice. Cases are recorded in which men and horses 

 have developed the disease after injuries, doubtless due to 

 the introduction into the wound, at the time, of soil or dust 

 containing the organism. 



If one introduce into a pocket beneath the skin of a sus- 

 ceptible animal about as much garden-earth as can be held 

 upon the point of a penknife, the animal frequently dies in 

 from twenty-four to forty-eight hours. The most conspic- 

 uous result found at autopsy is a wide-spread edema at 

 and about the site of inoculation. The edematous fluid is 

 in some places clear, while at others it may be stained with 

 blood; it is usually rich in bacilli (Fig. 102, A) and contains 

 gas-bubbles. Of the internal organs only the spleen shows 

 much damage. It is large, dark in color, and contains 

 numerous bacilli. If the autopsy be made immediately 

 after death, bacilli are rarely found in the blood of the 

 heart; but if deferred for several hours, the organisms will 

 be found in this locality also, a fact that speaks for their 

 multiplication in the body after death. At the moment of 

 death they are present in varying numbers in all the internal 

 viscera and on the serous surfaces of the organs. 



Of all animals mice are probably the most susceptible 

 to the action of this organism, and it is not rare to find it 

 in the heart's blood, even immediately after death. They 

 die, as a result of these inoculations, in from sixteen to 

 twenty hours. 



When a pure culture is used for inoculation a relatively 

 large amount must be employed, and this should be deposited 

 in the subcutaneous tissues at some distance from the surface. 



