io 
Seren, Ztschr. f, Hyg. u. Infectionskrankh. , v. 51, (2), pp. 181-196, 
1905), who first confirmed the above work of Uhlenhuth and then 
showed that the subcutaneous inoculation of large quantities of horse 
serum into guinea pigs produced at most a slight local reaction. He 
found on the other hand that the serum of certain other animals, e. g., 
cattle, hog, man, when injected subcutaneously into guinea pigs, pro- 
duced a local reaction and in large quantities caused necrosis. 
We took the temperature of a number of guinea pigs twice daily 
for eighteen days following the injection of large quantities of horse 
serum subcutaneously, in order to determine whether a febrile reac- 
tion followed. No marked deviation from the normal temperature 
was noted. 
ACTION OF ANTITOXIC HORSE SERUM UPON NORMAL GUINEA PIGS. 
It is a well-known fact that large quantities of horse serum contain- 
ing high antitoxic potency may be injected subcutaneously or into the 
peritoneal cavity of a normal guinea pig without causing symptoms. 
We use this method of testing the diphtheria antitoxin bought upon 
the open market to determine its freedom from bacterial and toxic 
impurities. Of the man}^ guinea pigs thus inoculated none has shown 
untoward effects except in the case of bacterial or toxic contamina- 
tions. This method of testing the purity of antitoxin is also used b}^ 
the manufacturers almost daily. We may therefore state that 
diphtheria antitoxic serum when injected into a normal guinea pig 
causes no symptoms. 
However, we present the following experimental data, which serve 
as controls for this work, because the normal guinea pigs in the follow- 
ing series have been inoculated into the peritoneal cavity with large 
quantities of the antitoxic horse serums subsequently used in this 
work. 
G. P. No. 300. Six c. c. antitoxic horse serum (Natl. IX. 19) injected into the peritoneal 
cavity. No symptoms. 
G. P. No. 301. Do. 
G. P. No. 302. Six c. c. antitoxic horse serum (Natl. V. 14) injected into the peritoneal 
cavity. No symptoms. 
G. P. No. 303. Do. 
G. P. No. 304. Six c. c. antitoxic horse serum (Natl. VIII. 18) injected into the peritoneal 
cavity. 
No symptoms. 
G. P. No. 305. Do. 
G. P. No. 306. Six c. c. antitoxic horse serum (NYBH 10B, Gibson) injected into the peri- 
toneal cavity. No symptoms. 
G. P. No. 307. Six c. c. antitoxic horse serum (NYBH 13C, Gibson) injected into the peri- 
toneal cavity. No sj^mptoms. 
G. P. No. 308. Six c. c. antitoxic horse serum (Alex. A 211) injected into the peritoneal 
cavity. No symptoms. 
G. P. No. 309. Six c. c. antitoxic horse serum (Natl. IX. 17) injected into the peritoneal 
cavity. No symptoms. 
G. F. No. 310. Do. 
