300 VETERINARY BACTERIOLOGY 



culture from the lungs, from the blood, and from various internal 

 organs of the body, without difficulty. The cultural characters 

 do not differ from those described for B. avisepticus. 



Physiology. The physiologic characters do not differ from those 

 of the group. 



Pathogenesis. Experimental Evidence. Inoculation of the 

 mouse, rabbit, and fowl lead to the same results as with the bacil- 

 lus of fowl cholera. Hogs die of septicemia after subcutaneous 

 injection. It has not proved generally possible to infect the hog 

 by feeding. That the organism is, under proper conditions, 



pathogenic for the hog appears to be well 

 - demonstrated, but that it can produce 



' 



an epizootic naturally among animals is 

 kv no means so well established. 

 (J Character of Disease and Lesions 



Produced. The characteristic lesions of 

 Q) this disease are generally to be found in 



Fig. l22.-Bacillus sui- the lungs ' althou S h the intestines may 



septicus in blood (after exhibit some changes and may closely 



deSchweinitz, Report Bu- simulate the conditions found in hog- 



reau of Animal Industry). cholera The ^^ may> fcherefor6j be 



denominated a pneumoenteritis. It may 



also appear in septicemia form. Punctiform hemorrhages are 

 generally to be observed, particularly in the kidneys. 



Immunity. As with the fowl-cholera bacillus, no true toxins 

 have been demonstrated. Both active and passive immunization 

 against the B. suisepticus have been accomplished. Active im- 

 munization has been attempted in* many different ways. The use 

 of killed and living cultures has not, in general, proved satis- 

 factory in immunizing the hog, although they have been success- 

 fully used in the preparation of antisera from the horse and other 

 animals. Weil has elaborated the following technic, making uso 

 of the so-called " natural aggressins " for the establishment of 

 immunity. A rabbit is injected intraperitoneally with 5 c.c. of 

 bouillon containing a drop of twenty-four-hour culture of a highly 

 virulent strain of the organism. The animal should die within 

 the next twenty-four hours. The exudate, varying in amount from 

 1 to 20 c.c., is pipetted off and sterilized by the addition of 0.5 



