Part VIL 
COMPARATIVE TOXICITY OF DIFFERENT HORSE SERUMS. 
Besredka and Steinhardt" believe that the French horse serums are 
much less toxic than those used by Otto^ and the serums used by us. 
Besredka and Steinhardt had a mortality of about 25 per cent when 
5 c. c. of serum was injected intraperitoneally at the second injection, 
whereas Otto’s and our percentage under similar conditions was much 
higher. Besredka kindly sent us a quantity of “'serum antidiph- 
terique” prepared at the Pasteur Institute and this serum was injected 
into a series of guinea pigs in order to compare its toxicity with the 
normal horse serum of our roan horse that we have used so much in 
these experiments. 
Toxicity of serum antidiphterique” {Pasteur Institute). 
Xo. 
G. P. 
First injection. 
Interval. 
Second injection. 
Result. 
7768 
0.142 c. c. toxine 5+3^0 
Days. 
76 
5 c. c. antitoxic 
Dead, 11 minutes. 
7774 
c. c. antitoxic horse 
serum (S. spi. 1351), 
subcutaneously. 
0.142 c. c. toxine b-hgio 
76 
horse serum (Pas- 
teur Institute), 
intraperitoneally. 
do .h. 
Dead, 10 minutes. 
7723 
7726 
c. c. antitoxic horse 
serum (S. spl. 1351), 
subcutaneously. 
0.142 c. c. toxine 5-4— 
83 
do . - 
Dead, 15 minutes. 
c. c. antitoxic horse 
serum (PD. 08022), 
subcutaneously. 
0.142 c. c. toxine 54-3^^ 
83 
1 
do 
Dead, 9 minutes. 
7849 
c. c. antitoxic horse 
serum (PD. 08022), 
subcutaneously. 
0.142 c. c. toxine 5^2Vo 
58 
' do 
Dead, 19 minutes. 
440 
c. c. antitoxic horse 
serum (A. 192), sub- 
cutaneously. 
0.0006 gm. tetanus tox- 
1 
i 56 
1 
Dead, 10 minutes. 
451 
ine A4-3-Vg. c. c. anti- ! 
toxic horse serum 
(Hoechst), subcu- i 
taneously. 
0.0006 gm. tetanus tox- 
56 
' do 
Dead, 10 minutes. 
ine A-^ 3^0 c. c. anti- 
toxic horse serum 
(Parke), subcutane- 
ously. 
1 
1 
1 
1 
oBesredka, A., and Steinhardt, Edna: De I’anaphylaxie et de I’anti-anaphylaxie 
ws-a-vis du serum de cheval. Ann. de I’Inst. Pasteur, Vol. 21, No. 2, Feb. 25, 1907, 
pp. 117-127. 
& Otto, R. : Das Theobald Smithschen Phiinomen der Serum- iJeberempfindlichkeit. 
Leuthold-Gedenkschr., Bd. 1, 1905. 
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