72 
The first result, viz, the acute death of the guinea pig, is of special 
interest to us, because it is the factor which determines the strength of 
the toxine and antitoxin. 
Guinea pigs dying acutely do so with great regularity on the fourth 
day, the actual time averaging about three days twelve hours. Occa- 
sionally guinea pigs will die between two and a half and three and a 
half days as a result of the injection of a minimal lethal dose or as the 
result of an injection of the mixture of toxine and antitoxin containing 
the L+ dose of the former and one immunity unit of the latter. In 
these cases the autopsy will often show a reason for this lack of resist- 
ance indicated by the severity of the reaction and especially the pres- 
ence of pleuritic exudates, or the guinea pig may have pneumonia or 
some other disease. Occasionally more resistant animals will die on 
the fifth day, rarely on the sixth day, and very exceptional!}" on the 
seventh, eighth, or ninth days. 
If the poison is not sufficient to kill the animal acutely as above 
described, paralysis may supervene. The symptoms of paralysis do 
not appear before the fourteenth day and usually show themselves in 
the legs. The hind legs are commonly affected first. The guinea pig 
not unusually recovers after marked paralytic symptoms, but ordina- 
rily the fore legs become limp and useless, respiration indicating 
phrenic involvement makes its appearance, and death supervenes. 
