IN SUSCEPTIBLE ANIMALS. 505 



it retains its blue color in presence of this bacillus, while the bacillus 

 previously described causes it to change to red. Neither phenol 

 nor indol is produced in solutions containing peptone (Bunzl-Federn) 

 another distinguishing character from the Bacillus septicsemise 

 haemorrhagiccE. This bacillus may be cultivated in slightly acid 

 media, which after a time acquire an alkaline reaction. 



In Smith's experiments this bacillus was found to resist desicca- 

 tion from nine days to several months, according to the thickness of 

 the layer dried upon the cover glass ; bacilli from an agar culture in 

 some experiments failed to grow after seventeen days, and in others 

 still gave cultures after four months. Bouillon cultures are steril- 

 ized in four minutes by a temperature of 70 C., in fifteen minutes 

 by 58 C., and in one hour by 54 C. (Smith). Novy has isolated 

 from cultures of the hog-cholera bacillus a toxic basic substance 

 which he calls susotoxin. This was obtained by Brieger's method ; 

 it is a yellowish-brown, syrup-like liquid, which, when injected into 

 rats in doses of 0.125 to 0.25 cubic centimetre, causes their death in 

 less than thirty-six hours. He also obtained by precipitation with 

 absolute alcohol, from cultures concentrated in a vacuum at 36 C., 

 a toxalbumin which when dried was in the form of a white powder 

 easily soluble in water. Rats died in three or four hours after re- 

 ceiving subcutaneously a dose of 0. 1 to 0. 5 gramme. 



Pathogenesis. Pathogenic for swine, rabbits, guinea-pigs, mice, 

 and pigeons. 



In certain parts of the United States the disease known as " hog 

 cholera " frequently prevails among swine as a fatal epidemic. It 

 may occur as an acute and quickly fatal septicaemia, or in a more 

 chronic form lasting from two to four weeks or even longer. In 

 the acute form death may occur within twenty-four hours, and hsem- 

 orrhagic extravasations are found upon the mucous and serous 

 membranes and in the parenchyma of the lungs, kidneys, and lym- 

 phatic glands. The spleen is greatly enlarged, soft, and dark in 

 color. In the chronic form of the disease the most notable changes 

 are found in the alimentary canal. These are most constant and 

 characteristic in the caecum and colon, which may be studded with 

 spherical, hard, necrotic masses or extensive diphtheritic patches. 

 According to Smith, the hsemorrhagic and necrotic form of the dis- 

 ease may exist at the same time in different animals of the same 

 herd. The bacilli are found in all of the organs, and especially in 

 the spleen, where they are associated in irregular colonies similar 

 to those of the typhoid bacillus. Smith has demonstrated their pre- 

 sence in urine taken from the bladder immediately after the death 

 of the animal, and states that the kidneys are almost always in- 



