31 
a toxine-antitoxin mixture containing sufficient toxon to invariably 
cause paralysis in control animals, is sufficient to prevent the develop- 
ment of paralysis and save life (see guinea pigs Xos. 8106, 8107, 
8110, and 8111, Table Xo. 3). 
SUMMARY AND CONCLUSIONS. 
Post-diphtheritic paralysis in the guinea pig is an almost exact 
counterpart of the same sequel in man. We are therefore able to 
bring forward experimental evidence showing the effect of antitoxin 
upon post-diphtheritic paralysis. 
In the guinea pig antitoxin can not influence the diphtheritic 
paralysis after the paralysis has appeared. 
Antitoxin has no influence in preventing post-diphtheritic paralysis 
if injected shortly before the paralysis develops. 
Antitoxin given twenty-four hours after the infection can save the 
hfe of the guinea pig and greatly modify the paralysis. 
Antitoxin given in a single large dose forty-eight hours after the 
infection did not modiW the paralysis or save life. Thus, in our 
experiments 4,000 units failed to modih^ the paralysis or save the 
life of guinea pigs weigliing about half a pound. Weight for weight 
this corresponds to 400,000 units for a 50 pound child. 
Antitoxin given in repeated injections beginning twenty-four or 
forty-eight hours following infection seems to have a more favorable 
effect upon the subsequent paralysis than a single injection. 
A very small quantity (1 unit) of antitoxin given twenty-four hours 
before or at the tune of infection in our experiments prevented the 
development of paralysis. 
In man we would expect more favorable results from the use of 
antitoxin than our work upon the guinea pig indicates, for we were 
dealing with an early and malignant form of experimental post- 
diphtheritic paralysis. This grave variety is, fortunately, rare in 
man. Further, we injected the entire charge of the poison directly 
into the tissues of the guinea pig, while in man the toxine is doubt- 
less elaborated more slowly. We may therefore assume that anti- 
toxic serum, given at a somewhat later period than in our work upon 
guinea pigs, would exert beneficial effects. 
The fact that one unit of antitoxin prevents paralysis and saves 
life when administered timely, whereas 4,000 units totally fails when 
delayed 48 hours, emphasizes the importance of using this sovereign 
remedy early. 
