CONTRIB UTION TO THE STUDY OF SERUM- THERAPY IN DIPHTHERIA. 66 7 
The serum that we obtain from horses keeps very well, with¬ 
out alteration, for all manipulations are performed with the 
greatest possible cleanliness. It is kept in the dark, in sterilized 
flasks to which nothing but a piece of melted camphor is 
added. The serum which is dried in vacuo can easily be sent 
at a distance, and reassumes its preventive qualities when dis¬ 
solved m eight or ten volumes of sterilized water. This solu¬ 
tion gives rise to a slightly transitory local swelling, which is 
never seen with the natural serum. 
. 14 may prove usefuI to condense an antitoxine which, as 
in milk, is too greatly diluted, but it appears to us to be a 
uselessprocedure to condense a serum which must again be 
diluted. 
IV. Action of the Serum in the Diphtheria of Mucous Sur¬ 
faces .—,Most experiments in serum-therapy have been practiced 
on animals under whose skin the substances were injected. 
Behring and his co-laborers have mentioned several, however, 
in which the injections were practiced upon the mucous mem¬ 
branes. These are very interesting, since, in practice, we do 
not find that diphtheria is developed in the midst of the tissues, 
but upon the mucous surfaces of the throat and larynx Hence 
we should cause a diphtheria of the mucous surfaces of animals, 
and see how it behaves under the action of the serum. This is 
the best way of preparing for the actual treatment of children. 
It is very easy to give a vulvar or vaginal diphtheria to a 
female guinea-pig. The mucous surface of the vulva and the 
vaginal entrance may be scratched, as was done by Lceffler, or, 
better still, may be slightly cauterized with a heated glass rod. 
Then the diphtheritic germs are applied. In a few hours there 
is redness and swelling, and the cedematous mucous membrane 
becomes covered with a grayish, adherent false membrane, 
ihere is strong fever, a vaginal discharge, and in two or three 
days we see the evidences of general poisoning ; the animal 
loses flesh and dies. This process has the advantage of show¬ 
ing the evolution of the local process, and the modifications 
brought about by treatment. This false membrane is of the 
