DIPHTHERIA. 301

stable so that the toxin is allowed to take its own time
to enter the tissues, can be recommended. Sometimes
it takes an hour to inject 500 c.cm. in this manner.

The amount of local reaction, edema, etc., the appetite
and general condition, the temperature-curve, and the
stability of the body-weight, must all be taken into con-
sideration, so that the administration shall not be too
rapid and the animal be thrown into a condition of
cachexia with toxic instead of antitoxic blood.

One of the principal things to be avoided is haste.
Too frequent or too large dosage is almost certain to kill
the animal.

Behring found that mixing the toxin with trichlorid
of ioclin lessened the irritant effect upon susceptible ani-
mals. I prefer not to use susceptible horses.

The suggestion of Prof. Pearson, that the large doses
of toxin might with readiness be introduced into the
trachea when the absorption is good, has been success-
fully accomplished by the author. The absorption seems
to take place without any change in the toxin, and to be
as rapid as from the subcutaneous tissue.

As the antitoxin protects the horse perfectly against
the toxin, a preliminary dose will enable one to omit all
the small preliminary doses of toxin, and render the
horse immune at once. Thus, I have frequently adminis-
tered roo c.cm. of antitoxin of about 100 units strength
to a horse one day and 500 c.cm. of strong toxin (500
factors) the next, This is just 500 times as much toxin
as has twice killed a horse in the laboratory. After the
lapse of a few clays the same quantity can be administered
again, and in a week a third time. In this rapid way
antitoxin can often be secured at short notice. It is yet
a question, however, whether tins method, modified from
Pawlowski, is as good and certain as the slow way sug-
gested by Behring.

The possibility of producing serum rapidly may depend
upon the method, but the production of strong serums de-
pends chiefly upon the horse and not upon its treatment