Part L 
CONTROL EXPERIMENTS, 
ACTION OF NORMAL HORSE SERUM UPON NORMAL GUINEA PIGS. 
Normal horse serum when injected into normal guinea pigs causes 
no symptoms. Large amounts, such as 6 or 10 c. c., may be injected 
into the peritoneal cavity of a guinea pig without any apparent 
inconvenience to the animal. When normal horse serum is injected 
subcutaneously into the guinea pig it is sometimes either absorbed 
very slowly or there is a slight local reaction, as indicated by edema 
and induration of the subcutaneous tissue at the site of injection. 
G. P. No. 2. a Six c. c. normal horse serum (roan horse) injected into the peritoneal cavity. 
No symptoms. 
G. P. No. 3. Ten c. c. normal horse serum (roan horse) injected into the peritoneal cavit} T . 
No symptoms. 
G. P. No. 63. Six c. c. normal horse serum (Sp. horse) injected into the peritoneal cavity. 
No symptoms. 
G. P. No. 64. Six c. c. normal horse serum (Jane horse) injected into the peritoneal cavity. 
No symptoms. 
G. P. No. 66. Six c. c. normal horse serum (Sam horse) injected into the peritoneal cavity 
No symptoms. 
G. P. No. 65. Six c. c. normal donkey serum (donkey No. 58) injected into the peritoneal 
cavity. No symptoms. 
G. P. No. 296. Six c. c. normal donkey serum injected into the peritoneal cavity. No 
symptoms. 
G. P. No. 297. Do. 
G. P. No. 298. Six c. c. normal horse serum (Sp.) injected into the peritoneal cavity. No 
symptoms. 
G. P. No. 299. Do. 
Specimens of serum from each one of the normal horses used in this 
work appear in the above series of guinea pigs, which serve as controls. 
Donke}^ serum is also harmless for normal guinea pigs and is just as 
toxic as horse serum to a sensitized guinea pig. 
LTilenhuth (Zur Kenntniss der giftigen Eigenschaften des Blut- 
serums, Ztschr. f. Hyg., v. 26, 1897, p. 384) found that normal horse 
serum, when injected intravenously into rabbits, is harmless. He 
injected as large quantities as 60 c. c. per 1 kilogram of rabbit and 
found that this caused no reaction at all. On the other hand he 
found that 11 c. c. of sheep serum, 12 c. c. of hog serum, or 6 c. c. of 
cattle serum per 1 kilogram of rabbit, when injected intravenously, 
caused the death of the animal. 
The nontoxic action of horse serum on animals was further shown 
by Hermann Pfeiffer (LTeber die nekrotisirende Wirkung normaler 
C G. P., abbreviation for guinea pig. The numbers refer to the laboratory serial numbers. 
(9) 
