678 
C. FISCH. 
first blood was drawn after such a treatment that had lasted for 
four months. The serum separated out nicely and was pre¬ 
served by means of pieces of camphor. 
For the future I shall follow the method of Huber and Blu- 
menthal* (mixing the freshly drawn blood with an equal 
amount of salt solution, thorough shaking, addition of i per 
cent, of chloroform, and filtration after 24 hours). While thus 
the antitoxic potency is the same as in serum prepared after the 
ordinary method, the output is twice as large. 
With appropriate methods it can be shown that this serum 
possesses bactericidal and antitoxic properties. It neutralizes 
comparatively large amounts of toxin, and effectively protects 
animals against infection. .10 c. c. is sufficient to counteract 
inoculation with a fatal dose of living bacilli in a rabbit, while 
it takes a little more to protect a guinea-pig. 
.5 c. c. when injected not later than 24 hours after inocula¬ 
tion with the fatal dose cures a rabbit in most cases, but not 
with absolute certainty. It seems that individual rabbits are 
much more susceptible than others, so I tried to use animals as 
far as possible of the same size, sex, and breed. Larger amounts 
of serum were not tried on these animals for practical reasons. 
Serum treatment was unsuccessful in all cases, where the 
iime between infection and beginning of the treatment exceeded 
36 hours (in rabbits). 
A more accurate series of experiments were conducted on a 
number of young hogs. Three of them were injected with vary¬ 
ing amounts of serum, and one, three, and fourteen days, respec¬ 
tively, afterwards injected intravenously with twice the fatal 
dose of a virulent culture. All of the animals remained healthy 
and undisturbed. A fourth animal that had not been treated 
developed promptly on injection of the bacilli a typical case of 
hog cholera. This experiment was repeated several times with 
the same results. It was found that one part of the serum, as it 
is now, protects 16,000 parts of hog, so that for a medium-sized 
animal a quantity of 5 c. c. about would be necessary for a pro- 
* Berl. klin. Wochenschr., Aug. 2, 1897. 
