668 
E. ROUX, L. MARTIN AND A. CHAILLOU. 
same nature as that observed in children, and contains diph¬ 
theritic and foreign bacteria. 
i Serum injected p revent at iv ely .—Female guinea-pigs always 
resist the action of the virus when a sufficient amount of the 
serum is injected prior to the vaginal inoculation. In proceed¬ 
ing in the manner already described, there always occurs a false 
membrane ; but, while in the control cases there is a red and 
oedematous mucous membrane, with high fever, and a bad gen¬ 
eral state, the treated females show less extensive redness, less 
swelling, and a mild degree of fever. From the second day the 
local lesions diminish and the mucous membranes show a 
beginning reparative action. Females of the same weight were 
experimented on. Those that were unprotected died on the 
sixth day, while those which received a preventive inoculation 
equalling i -10,000 part of their weight recovered. When the 
dose of serum is not sufficiently strong, the animals apparently 
recover, but succumb later on to cachexia. 1 he same things 
occur if the serum is injected at the same time that the inocula¬ 
tion is made. 
False membranes may also be produced on the ear of rabbits. 
A rubber ring is first placed around the ear, to cause a slight 
oedema. Then the skin is lightly burned and inoculated with 
diphtheritic bacilli. The rubber ring is then removed, and, as the 
exudation keeps the surface humid a fine false membrane is formed. 
By microscopic sections of such ear at various stages of the disease 
it is very easy to study the changes that occur in the tissues. 
2. Serum injected after inoculation .— The false membrane 
is well developed after twelve hours, and the redness and swell¬ 
ing of the vulva are marked. If, at this time, an injection of 
serum of from a io,ooothto a i,oooth part of the weight of the 
animal is made, the animal will recover very well. A few 
hours after the oedema is arrested the swelling diminishes, and 
on the second day the false membranes become detached. 
When the mucous membrane is healed no more diphtheritic 
bacilli can be found. 
One is astonished at the rapidity with which the false mem- 
