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X, B, 1 Ruediger: Preparation of Tetanus Antitoxin 57 
units of tetanus antitoxin, 1,000 units of which were given 
on November 10, 1913, and 1,000 units were given two weeks 
later, on November 24, 1913. The injection of tetanus toxin 
was begun on November 10, 1918; injections were given at 
intervals of a week, and the doses were increased gradually. 
Twelve liters of blood were withdrawn in the latter part of 
April, 1914, from which were obtained 5 liters of serum testing 
250 units of tetanus antitoxin per cubic centimeter. After the 
bleeding the injections of tetanus toxin were continued. On 
June 9, 1914, the horse was bled 5 liters, which yielded 2 liters 
of serum that contained 250 units of tetanus antitoxin per cubic 
centimeter. After this bleeding large doses of toxin—750, 1,000, . 
1,250, 1,500, and 2,000 cubic centimeters—were injected. Ten 
liters of blood withdrawn on July 21, 1914, yielded 3 liters of 
serum with 300 units of tetanus antitoxin per cubic centimeter. 
Four liters of serum, which were obtained from 10 liters of 
blood withdrawn on July 24, 1914, tested 275 units per cubic 
centimeter. The injections of large quantities of toxin did not 
greatly increase the antitoxin content in the serum of the 
horse. Three injections of tetanus toxin were given—one dose 
of 500 cubic centimeters on July 27, 1914, one dose of 750 
cubic centimeters on August 3, 1914, and one dose of 1,000 
cubic centimeters on August 10, 1914. On August 18, 1914, the 
horse was bled 10 liters and 2.5 liters of serum were obtained, 
which tested 150 units per cubic centimeter. A bleeding of 
10 liters on August 21, 1914, yielded 4 liters of serum with 100 
units of antitoxin per cubic centimeter. 
After the bleeding on August 21, 1914, toxin was given in 
4 injections—500 cubic centimeters on August 24, 1914, 700 cubic 
centimeters on August 31, 1914, 800 cubic centimeters on Sep- 
tember 7, 1914, and 1,000 cubic centimeters on September 14, 
1914. On September 21, 1914, the horse was bled 10 liters and 
3.5 liters of serum were obtained, which contained 75 units of 
tetanus antitoxin per cubic centimeter. 
Ten liters of blood were withdrawn on September 23, 1914, 
which yielded 4 liters of serum with about 75 units of anti- 
toxin per cubic centimeter. On September 25, 1914, horse 8 
was bled to death; 14 liters of blood were obtained, which yielded 
6 liters of serum that contained a little more than 50 units of 
antitoxin per cubic centimeter. 
Horse 8 received in all 19,323.5 cubic centimeters of tetanus 
toxin. It furnished 91 liters of blood, which yielded 34 liters of 
antitetanic serum or 5,537,000 units of tetanus antitoxin. If 
