IN SUSCEPTIBLE ANIMALS. 437 



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- 

 volved, as shown by the presence of albumin and tube casts in the 

 urine. 



An extremely minute quantity of a bouillon culture injected be- 

 neath the skin of a rabbit causes its death in from seven to twelve 

 days ; a larger quantity may produce a fatal result in five days ; in- 

 travenous injections of very small amounts may be fatal within 

 forty-eight hours. After a subcutaneous injection the animal re- 

 mains in apparent good health for three or four days, after which it 

 loses its appetite and is indisposed to move ; several days before 

 death the temperature is suddenly elevated from 2 to 3 C., and it 

 remains high until the fatal termination. At the autopsy the spleen 

 is found to be enlarged and of a dark-red color ; the liver is studded 

 with small, yellowish- white, necrotic foci; the kidneys have under- 

 gone parenchymatous changes ; the heart is fatty ; and the intestinal 

 mucous membrane is more or less marked with hsemorrhagic extra- 

 vasations. The bacilli are found in all of the organs. In house 

 mice the results of experimental inoculations are similar to those in 

 rabbits. Guinea-pigs succumb when inoculated subcutaneously with 

 one-tenth cubic centimetre ; pigeons require a still larger dose 

 about three-quarters of a cubic centimetre. Swine are killed by the 

 intravenous injection of one to two cubic centimetres of a recent 

 bouillon culture, but, as a rule, do not succumb to subcutaneous 

 injections. Cultures recently obtained from diseased animals are 

 more virulent than those which have been propagated for a consider- 

 able time in artificial media. 



Smith has described a variety of the hog-cholera bacillus obtained during- 

 an epidemic in which the disease was of longer duration about four weeks 

 than is usual, and in which there was commonly found at the autopsy a 

 diphtheritic inflammation of the mucous membrane of the stomach. This 

 bacillus differed from the typical form by being somewhat larger and in 

 forming considerably larger colonies in gelatin plates two or three times 



