15 
able to bring forward experimental evidence shovdng the relation of 
antitoxin to post-diphtheritic paralysis. 
It is now well knovm that guinea pigs may develop paralysis fol- 
lovdng the injection of a siiblethal dose of toxine or the injection of a 
toxine-antitoxin mdxture in which the toxine is but partialh" neu- 
tralized. As will be seen by our experiments, paralysis ma}" uner- 
ringly be produced in guinea pigs vdth a partially neutralized toxine. 
We look upon the paraWsis as a ‘Aoxon” poisoning. 
By no means every guinea pig that shows symptoms of post- 
diphtheritic parah^sis dies. Recovery from this sequel in the guinea 
pig is frequent and depends entire!}^ upon the amount of toxon in the 
toxine-antitoxin mixture. It is ver}^ eas}- to mix the toxine and 
antitoxin in such proportion that ever}" guinea pig will develop post- 
diphtheritic paralysis and die. By adding a little more antitoxin 
or a little less toxine to the mixture the guinea pigs will develop mild 
paralytic symptoms from which almost all will recover. 
Almost all of our work was done with partially neutralized mix- 
tures containing sufficient toxon to produce early and malignant 
paralysis. As far as the guinea pig is concerned paralysis can rarely 
be detected before the fourteenth day. The first indications are a 
softness of the abdominal muscles near the site of the injection. The 
weakness gradually spreads to the extremities and finally to the 
^ muscles of respiration. In the guinea pig paral}^sis occurring early 
: is almost, always followed by death; symptoms appearing late are 
t apt to be mild, and complete recovery follows. 
We can confirm the observations of Levds,® in that the paralysis 
in the guinea pig may be slight, affecting but one limb or somewhat 
embarrassing the respiration; or, it may be severe and cause sudden 
or gradual death. It may last for two days or two weeks, or it may 
, terminate fatally at any time. The paralysis is never permanent. 
: Levds ® recently made a study of diphtheria toxone paralysis in 
t the guinea pig, and concludes as follows: 
1. By grouping and analyzing the records of the guinea pigs used 
in a large number of routine tests of the strength of recently prepared 
toxins it is shown that the crude toxins, produced by the same culture 
of diphtheria bacillus under conditions which are identical within 
limits which it is possible to determine at the present time, differ 
greatly in the amount of toxon or paralysis-producing poison which 
they contain. 
2. Using old crude toxins which have become relatively stable in 
composition, in mixtures with antitoxin on the present Ehrlich 
system, it is shown that — 
{a) Guinea pigs are somewhat more susceptible to the action of 
» « Lewis, Paul A.: Diphtheria toxon paralysis in the guinea pig. .lourn. med. 
research, vol. 15, no. 3, n. s., vol. 10, no. 3, Dec., 1906, pp. 469-4S2. 
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