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111
1936 was a poor year from the immunisation point of viewin
the Borough. Every effort was made to keep up the herd immunity,
but owing to the relative freedom of the district from Diphtheria,
the interest of the parents in artificial immunisation was
difficult to rouse. Children also who had been inoculated against
Diphtheria three years ago were offered re-inoculation to keep up
their level of blood immunity. To begin with, and as reported in
the Annual Report of 1935, all children who had been immunised
three years ago were Schick tested, and only those found to have
relapsed into positive Schick reactors were re-immunised. At
present the Schick test is the only indicator at our disposal for widespread
use in a community test to the level of blood immunity
reached. That Diphtheria can and does occur in subjects who have
been rendered Schick negative, seems to us an indication that
to a large extent our efforts in this line were waste of time. Here and
there, all over the country, from time to time clinical Diphtheria
is found in those who are or who have been rendered Schick negative,
and although the fact that the great majority of these cases are mild
or moderate attacks of the disease is matter for congratulation, it
is unsatisfactory that "Schick negative" is not synonymous with
"immune."
In an article published in the Lancet in March 1935, H.J.
Parish and J. Wright gave data of investigations made by them into
the "Schick level" They found that in Schick negative reactors
there might be a titre of immunity only 1/16th of What is supposed
to result when inoculation has produced a negative Schick reaction.
In the same article the writers gave figures from some preliminary
experiments with "multiple Schick toxins" where the combining
power was 4 to 10 times as strong as the material commonly used.
With "fourfold" Schick toxin, negative Schick reactions were
obtained where the titre was only l/3rd that which was supposed
to result from inoculation which rendered the subject Schick negative.
It must be seen then, that the Schick test as commonly
used is not a sufficient index of the level of immunity. During
part of 1935 and 1936 tests were made of comparison between the
numbers of Schick positive reactors obtained when ordinary Schick
toxin and fourfold Schick toxin were used on the same person.
A total of over 500 cases are recorded and the results are tabulated
below. The precedure was as follows:—a control—fourfold—was
injected into the right arm, and ordinary Schick toxin was injected