526 
E. A. Y. SOHWEINITZ. 
which had the preventive treatment are now and have been 
quite well, though continually exposed for five weeks to every 
opportunity for contagion. 
Experiment VII.—This experiment is a step in ad¬ 
vance of those already recorded, and although not quite so 
conclusive, indicate that the proper methods have been 
adopted. 
A pure chemical compound prepared synthetically in the 
laboratory, was used for treating the guinea-pigs. Three ani¬ 
mals were taken, and this compound was administered to them 
by the method already used. There was a slight rise in tem¬ 
perature of the animals and swelling and soreness at the point 
of injection. After this had healed, these animals and two 
checks were inoculated with tV c. c. of hog-cholera culture. 
The checks died in eight and nine days. The animals which 
had been previously treated became ill, two dying five and 
six days after the checks. The third entirely recovered. 
Post-mortem examination of the two that died showed the 
following: At the point of inoculation the skin had sloughed 
away over an area of i sq. cm. The superficial muscular 
layer was necrosed over an area of about 3 sq. cm. and to a 
depth of 1 mm., lymphatics in the fold of the knee much en¬ 
larged; Peyer’s patches enlarged and pigmented; spleen very 
slightly enlarged and not discolored ; kidenys reddened; lungs 
normal. Cover-glass preparation from the spleen showed a 
few hog-cholera germs. On both sides of the spinal column 
were several grayish tubercles, from ^ to 2 mm. in diameter, 
lying just beneath the peritoneum. This material is being 
more fully tested, and experiments which promise to be suc¬ 
cessful are also being made upon hogs. Autopsies made from 
the animals of experiment VI, three or four weeks after their 
recovery, showed that the parts were perfectly normal, not 
even a scar being left upon the skin, and the immunity pro¬ 
duced was therefore perfect. 
It is important to add that in all the experiments great care 
was taken that the solutions used were free from germs, cul¬ 
tures always being made. In cases in which the albumin is 
used this is particularly important. A single precipitation 
