THE PRODUCTION OF IMMUNITY. 
523 
tissue was infiltrated with a greyish-white substance, and the 
superficial layer of muscles over the inner side of thigh, and 
4 square centimeters of the abdominal wall were necrosed, 
liver pale; spleen much enlarged, dark-colored, and friable. 
Cover-glass preparations from the spleen showed a large 
number of hog cholera germs. Both ventricular walls of the 
heart were light-greyish and very brittle (necrosed). The 
other guinea-pig of this set was quite ill for ten days, with a 
large swelling at the point of inoculation. This finally open¬ 
ed and healed, and the animal was quite well within three 
weeks after the inoculation, and has continud so to date—five 
months. 
Experiment II.—The next series of experiments were 
made with sucholo-albumin from beef-infusion and peptone 
culture-media. 
Two guinea-pigs were again selected and treated with 
about 0.008 gramme each of sucholo-albumin. There was a 
slight rise of temperature in the animals and the formation of 
a small, hard lump at the point of injection. This disappear¬ 
ed by the eighth day, and the animals were quite well. Two 
more guinea-pigs were now taken as checks, and all four ani¬ 
mals were inoculated with o. 10 c. c. of hog cholera culture. 
The checks died within seven days. The post-mortem ap¬ 
pearances were practically the same as those noted in the first 
series. The two guinea-pigs which had been treated with the 
sucholo-albumin died ten days after the checks. This indi¬ 
cates considerable resistance to the disease. Autopsy show¬ 
ed, at the point of injection with the albumin, the subcuta¬ 
neous tissue thick and reddened. The animals were consid¬ 
erably emaciated. At the point of inoculation a cyst the size 
of a walnut, and composed of a grayish, purulent substance, 
was also found. The muscular wall surrounding this was 
sprinkled with punctiform haemorrhages. Peyer’s patches 
swollen and pigmented; mucous membrane of small intestine 
covered with a dry, yellowish, firm layer of mucus; stomach 
contained a considerable quantity of liquid ; liver pale, and 
showed fatty degeneration; spleen slightly enlarged and dark. 
Cover-glass preparations showed no germs, but a culture 
