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various factors such as the amount of circulating antitoxin, the
degree of virulence of the infection, and the duration of the Schick
negative phase, which have important bearings on the problem of
immunisation.
In this brief sketch I have endeavoured to trace the great
advance in our knowledge of the prophylactic measures that can be
taken against diphtheria and the success attained by carrying them
out efficiently. It is satisfactory to note that in this country, at
the present time, much is being done to stimulate a widespread
adoption of these measures for the protection of the community."
(1—Lancet, March 9th, 1935, p. 579. 2—Journal Path, and Bad.,
1931, Vol. 34, p. 667.)
Surgeon-Captatn Sheldon F. Dudley, R.N. (Deputy .Medical
Director, R.N.).
"Immunisation at Greenwich Naval School.
Not so very long ago diphtheria was attributed to drains and
smells, and I suppose most of us remember occasions when our
parents expected we would all get diphtheria because something
had gone wrong with the sanitary arrangements.
Time passed, and it became accepted that diphtheria was
caused by a specific microbe. This discovery led to the hope that
we had now only to keep our eyes open and segregate all cases of
diphtheria in isolation hospitals in order to eradicate the disease,
because it was believed that every case of diphtheria must have
caught the infection from some other case of diphtheria. Therefore
it was most disappointing when competent statisticians informed
us that they could find no evidence that the extensive use of isolation
hospitals had had any effect on the prevalence of diphtheria.
The negative effect of the isolation of diphtheria cases was
puzzling until it was realised that certain people could be infected
with virulent diphtheria bacilli without exhibiting any symptoms
of ill health. These subjects are the so-called "carriers" of
diphtheria. When all other conditions are equal, the average case
of diphtheria is a more dangerous source of infection than the
average carrier; but the case is isolated or immobilised in bed,
while the carrier continues to go about among his fellows unconsciously
distributing the germs of diphtheria far and wide.
With the discovery of carriers hope rose once more in the
minds of those responsible for the public health; for, it was said,
we had only to search diligently for carriers among the contacts of