3
3. Cutaneous Reaction in Antirabic Inoculations.
The method of treatment in this Institute is to inject once daily 4 cc. of an
emulsion of fresh fixed virus for a period of 14 days. The injections are started
about 2 cm. below the umbilicus and 3 cm. from the middle line, and 2 cc. are
injected on each side. The succeeding injections are made in straight lines directly
below the first, about 1·5 cm. separating each puncture from the one above it. On
the eighth day the injections are made on a level with, and 2·5 c m . o u t s i d e , t h e f i r s t ,
on the ninth day outside the second and so on, until at the end of the fourteenth day
the patient presents two double rows of punctures, fourteen on each side.
In perhaps a quarter of the total number of patients the injections give rise to
no redness or swelling whatever, only the needle marks are seen during and at the
end of the treatment, and itching is but rarely complained of, so that it is only in
persons who happen to have a short space between the umbilicus and pubes, and in
small children, that any alteration has to be made in the, routine lines.
It has long been noticed, however, that the last of the first row of injections,
or 7th, and much more frequently the first of the second row, or the 8th, gives rise
to a slightly elevated, hyperæmic patch, of irregular outline, from 2·5 cm. in
diameter.
The 9th injection and also the 10th and 11th then have to be more spaced out,
for a puncture into one of these hyperæmic areas leads to a little bleeding which it
is as well to avoid. In such persons the 12th, 13th and 14th injections cannot be
fitted into the space available, and a third row has to be formed, or one or two put
in above the umbilicus. The 8th, 9th and 10th injections are the ones which cause
the most noticeable reaction ; and the patients who are affected complain a good
deal of the itching. The 11th-14th injections give less reaction and the itching
becomes less.
When a reaction appears after the first or second injections it is generally a sign
that the health of the patient is not perfect, he is alcoholic, dyspeptic, or obese
and the reaction is probably an indication that the absorptive power of his sub-
cutaneous tissue is not good. It has not been noticed that such persons exhibit
more severe reactions about the seventh day than healthy subjects.
Reactions on the eighth day have seldom been observed in persons with no
subcutaneous fatty layer and a skin so loose that a prominent moveable ball is the
immediate result of an injection. On the other hand, women, who have a thick
layer of sub-cutaneous fat, seem to react but rarely.
An eighth day reaction consisting merely of a pink area, say 3 cm. in diameter,
without swelling or itching, which would pass unnoticed in a dark skinned Indian, is
obvious in unpigmented skins.
The reaction has never been regarded in this Institute as indicative of a
specific susceptibility to rabies, nor can it be supposed to afford any information as
to the progress of immunity as a result of the inoculations. Stimson, who has lately
called attention to this reaction for the first time in print (Journal of Medical Research,
November 1910) has been more precise in his observations than we have, and gives
a graphic representation of the intensity of the reaction which culminates on the
eighth and ninth days ; but he does not seem to draw a sharp enough distinction
between the really specific reaction, which, as our observations go, does not manifest
itself earlier than the sixth day and most frequently the eighth, and the swelling due
to local irritation and faulty absorptive power in persons who are below par in health.
The reaction is evanescent in a certain number of people and nearly all trace
of it may have disappeared within 24 hours.
Stimson has observed also that, when a reaction occurs suddenly after any one
puncture, it may be evident, not at that site only, but at the site of several previous
punctures. This is beyond our experience, which is that it is not uncommon for
several punctures to be in reaction at the same time, i.e., the reaction at any one spot
may last several days. We have never noticed for example the 8th puncture to
show a reaction after the loth injection : if the 8th puncture intends to react it will