23 
The difference in our results may be accounted for by the difference 
in toxicity of the French and the American serums, or by differences 
in susceptibility of the animals used. 
Table No. 17. — Ether. 
G.P. 
No. 
Treatment. 
Result. 
9419 
0.23 c. c. toxine No. 7+1/440 c. c. antitoxic horse serum (Alex. A276) . 55 
days later tested as follows : The animal was first trephined, then deeply 
narcotized with ether, and in the stage of complete relaxation injected 
with 0.25 c. c. antitoxic horse serum (Mul. 2295) into the brain. The 
etherization was continued several minutes longer. 
Died. 
9376 
0.23 c.c. toxine No. 7+1/1060 c. c. antitoxic horse serum (NY 306). 62 days 
later etherized and tested as above with 0.1 c. c. same serum. 
Died. 
9374 
0.23 c.c. toxine No. 7+1/1080 c.c. antitoxic horse serum (NY 306). 62 days 
later etherized and tested as above with 0.25 c. c. same serum. 
Died. 
9175 
0.23 c. c. toxine No. 7+1/540 c. c. antitoxic horse serum (Mul. 24.39). 106 
days later etherized and tested with 0.2 c. c. normal horse (roan) serum 
into brain. 
Died in 5 minutes. 
9174 
0.23 c. c. toxine No. 7+1/450 c. c. antitoxic horse serum (Mul. 2429). 106 
days later etherized and tested with 0.2 c. c. normal horse (roan) serum 
into brain. 
Died in 5 minutes. 
9678 
0.23 c. c. toxine No. 7+1/320 c. c. antitoxic horse serum (Alex. A245.) 73 
i days later etherized and tested with 0.2 c. c. normal horse (Frank) serum 
into brain. 
Died in 10 minutes. 
9581 
0.23 c. c. toxine No. 7+1/280 c. c. antitoxic horse serum (.\lex. A245) . 73 
days later etherized and tested with 0.2 c.c. normal horse (Frank) serum 
into brain. 
Recovered. 
Next day 6 c. c. normal horse (Frank) serum intraperitoneally 
No symptoms. 
9582 
0.23 c. c. toxine No. 7+1/280 c. c. antitoxic horse serum (Alex. A245). 65 
days later etherized and tested with 0.2 c. c. antitoxic horse serum 
1 (Lyons) into brain. 
Died in few minutes. 
ATTEMPTS TO NEUTRALIZE HORSE SERUM WITH THE BRAIN 
AND BLOOD OF SENSITIZED GUINEA PIGS. 
We made further attempts to neutralize the toxic action of horse 
serum by first treating it with sensitized guinea pig serum and also 
wdth the brain substance of sensitized guinea pigs. These attempts 
all proved futile. 
In the following experiments normal horse serum was mixed with 
equal parts of sensitized guinea pig serum, and kept at room tem- 
perature twenty-four hours. 
The brain of a sensitive guinea pig was removed under aseptic- 
precautions, mixed with about 20 c. c. of normal horse serum, ground 
up in a mortar, kept at room temperature for twenty-four hours, 
and then strained. 
