THE BACTERIA 2138 
198. Preparation of antitoxin. It has been found possible 
to secure from horses and mules an antitoxin that will coun- 
teract diphtheria toxins in the human body. These animals 
are naturally immune to diphtheria, but by injecting into their 
bodies toxins produced in beef broth by diphtheria bacteria, 
this natural immunity is greatly increased. First into the ani- 
mal’s body there is injected a small amount of toxin. This 
process is repeated, with an increasing amount, at intervals of 
a week or a little less, for a period of two or three months. 
The animal finally withstands, with no ill consequences, an 
amount of toxin that would have proved fatal if used at first. 
At this time some of the blood is drawn off and allowed to 
clot, and the antitoxic serum is sterilized. This antitoxic 
serum is usually concentrated, in order to make it possible to 
inject the desired strength of antitoxin without an unneces- 
sarily large amount of liquid. After its relative strength is 
determined, it is sealed in small bottles and is ready for dis- 
tribution. A human being who has diphtheria may then be 
given the proper amount of antitoxin. If it is properly given, 
and given early enough, the attack is defeated.t 
AVERAGE ANNUAL DEATH RATE FROM DIPHTHERIA 
PER 10,000 POPULATION 2 
Before use of Antitoxin 
antitoxin period 
(1885-1894) (1895-1904) 
WRADIS?.” oy:tak: oy 3 . 8 ‘ 6.41 1.49 
Berlin . . . eis : ‘ 9.93 2.95 
Vienna. . é a sens 8.14 2.95 
London eee 48 08 5 4.85 3.88 
New Yorki« isn sj an 0 en eS 15.19 6.62 
Boston a % m): a 11.76 6.34 
Baltimore bene i ae 7.84 4.99 
Chicago® . 3. « a « fe oe ew 14.29 5.13 
1 A few inexcusable cases have occurred where impure antitoxin was used. 
° Jordan, E. O., General Bacteriology, 1911. 
3 The use of antitoxin was begun in 1895-1896 ; the death rate dropped 
from 12.01 in 1895 to 7.62 in 1896. 
