INFECTIOUS SWINE DISEASES IN THE UNITED STATES. 
825 
18. Pigs are not usually afifected by sub¬ 
cutaneous injection of small quantities of 
culture. If the pigs are killed within i 
to 3 weeks the bacilli are found in the local 
lesion and certain of the lymphatic 
glands.* batal results are reported in a 
few cases by these injections. 
19. Feeding cultures to pigs which have 
fasted for 24 hours produces extensive in¬ 
testinal lesions with fatal results. 
20. Intravenous inoculation into pigs 
causes either an acute septicaemia or a 
chronic form of the disease in which are 
produced quite typical round, firm, ele¬ 
vated ulcers. 
* Moore, What becomes of hog-cholera an 
taneously in small quantities in pigs. Bulletin ] 
18. Pigs are not usually afifected by the 
subcutaneous injection of small quantities 
of culture. The bacilli are not found ex¬ 
cept in the local lesion. In a few cases 
fatal results are reported. 
19. Feeding cultures to pigs usually pro¬ 
duces no effect. 
20. Intravenous inoculation into pigs 
usually produces a septic form of the dis¬ 
ease which kills in from i to 2 days. In¬ 
oculation into the lungs causes pleuritis, 
usually accompanied with pneumonia. 
swine-plague bacteria when injected subcu- 
I. 6, Bureau of Animal Industry, 1894, p. 101. 
The results of inoculation experiments with these bacteria 
are conclusive in establishing their causal relations to their 
respective diseases. In explaining the differences in results 
reported by different investigators the method, age, and kind 
of culture and the degree of virulence of the bacteria used, to¬ 
gether with the age and condition of the swine inoculated, must 
be taken into consideration. 
Several varieties of the hog-cholera bacillus have been 
recognized. As early as 1890 Smith * called attention to a 
variety of this organism which was more saprophytic in its 
tendencies than the form usually encountered. In 1894 he 
described seven varieties f of the hog-cholera bacillus which 
had been isolated from swine. These varieties differ either 
morphologically, in the character of their growth on ordinary 
media, in the quantity of gas produced in glucose bouillon or 
in their pathogenesis for rabbits. In addition to these. Smith 
places the bacillus found by him in aborting mares,^ Bacillus 
enteritidis of Gaertner and Bacillus typhi murium of Loeffler 
in this group. 
*New York Medical Journal, Nov. i, 1890, p. 485. 
t These are designated as B. cholerce suis 
bacteria. Bulletin No. 6, Bureau of Animal Industry, 1894. 
I Bulletin No. 3, Bureau of Animal Industry, 1893. 
1 he hog-cholera group 01 
