EXPERIMENTS IN" VACCINATION AGAINST ANTHRAX. 
Hyperimmunization of horses Nos. 48 and 96. 
Date. 
Amount of virus given each horse. 
Result. 
1914. 
Sept. 29 
0.01 loopful 
No apparent reaction in horse 48. Horse 
96 developed anthrax at point of inocula- 
tion; large swelling; edema of neighbor- 
ing tissue. Persisted about one week. 
No noticeable reaction in either animal. 
Oct. 24 
1 loopful 
Nov. 15 
10 loopfuls 
Do. 
Dec. 9 
5 c. c. of an emulsion, representing one- 
half growth of agar culture. 
20 c. c. of emulsion, representing washing 
of growth from 2 agar cultures. 
30 c. c. of emulsion, growth from 8 agar 
cultures. 
40 c. c. of emulsion, growth from 2 mass 
cultures from flasks, surface area 6 by 
2J inches. 
50 c. c. of emulsion, growth from 4 mass 
cultures from flasks, surface area 6 by 
2J inches. 
50 c. c. of emulsion, growth from 8 mass 
cultures from flasks, surface area 6 by 
2§ inches. 
do. . .. 
Horse 48 showed a temperature of 102.2° 
Dec. 29 
the following day; horse 96, 101°. Both 
animals developed a small, hard nodule 
at point of inoculation. 
Both animals developed small abscess at 
point of inoculation. 
Jan. 19 
Feb. 6 
Slight reaction in horse 96. Horse 48 
showed quite an intensive reaction, devel- 
oping a large swelling at point of inocu- 
lation; persisted several days. 
No apparent reaction. 
Slight local reaction in each case. 
Do. 
Mar.5 
Mar. 31 
Apr. 19 
do 
Slight rise in temperature in both cases. 
Slight temperature and local reaction. 
Do. 
May 11 
do.. . 
May 24 
do 
June 12 
...do... 
Slight local reaction. 
In the above work four strains of anthrax bacilli were used, known 
to us as "Davis," "6071," "Burt," and "Boener"— the first two 
strains being highly virulent types and the latter two very much 
weaker. In all cases where the larger amounts of the virus were 
given the injections were made at 4 to 6 different points in order to 
minimize abscess formation. 
It might be well also to state here that the irregularity in the time 
between injections was due to the fact that this work was interfered 
with by the outbreak of foot-and-mouth disease in this country, and 
for this reason it was also impossible to subject the blood to periodical 
tests to ascertain its immunizing value at the different intervals 
between injections. Experience proved that horses may produce 
highly potent serum following the injection of the first or second 
mass cultures. It is therefore advisable to subject the blood of the 
animals to periodical tests for potency throughout the course of 
immunization. 
On June 25, 1915, 6 liters of blood were drawn from each horse 
into the glass bleeding cylinders previously described. Since this 
date these animals have been bled regularly, 6 liters being taken 
from each horse, and an injection of virus made in the intervals 
between bleedings. 
SERUM TESTS. 
In standardizing our serum, that taken from each horse was tested 
separately. The following procedure was carried out: Three series 
