412 BACTERIOLOGY. 



stained by the methods usually employed in spore- 

 staining. 



Pathogenesis. When susceptible animals, especially 

 guinea-pigs, are inoculated in the deeper subcutaneous 

 cellular tissues with pure cultures of this organism, or 

 with bits of tissue from the affected area of another 

 animal dead of the disease, death ensues in from one to 

 two days. It is preceded by rise of temperature, loss of 

 appetite, and general indisposition. The seat of inocula- 

 tion is swollen and painful, and drops of bloody serum 

 may sometimes be seen exuding from it. At autopsy the 

 subcutaneous cellular tissues and underlying muscles 

 present a condition of emphysema and extreme oedema. 

 The oedematous fluid is often blood-stained and the 

 muscles are of a blackish or blackish-brown color. The 

 lymphatic glands are markedly hypersemic. The in- 

 ternal viscera present but little alteration visible to the 

 naked eye. In the blood-stained serous fluid about the 

 point of inoculation short bacilli are present in large 

 numbers. These often present slight swellings at the 

 middle or near the end. They are not seen as threads, 

 but lie singly in the tissues. Occasionally two will be 

 seen joined end to end. If the autopsy be made imme- 

 diately after death these organisms may not be detected 

 in the internal organs, but if not made until after a few 

 hours they will be found there also. In fresh autopsies 

 only vegetative forms of the organism may be found, 

 but later (in from twenty to twenty-four hours) spore- 

 bearing rods may be detected. (How does this compare 

 with bacillus anthracis?) By successive inoculations of 

 susceptible animals with the serous fluid from the seat 

 of inoculation of the dead animal, the disease may be 

 reproduced. 



