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77
[1899
Many theories have been advanced by scientists as to the great
variations that have occurred with respect to this disease, but it
seems to me that the strongest arguments yet adduced have been
those advanced by Dr. Newsholme, in his work on Epidemic
Diphtheria, where he shows by numerous diagrams that, to quote,
his words, " Diphtheria only becomes epidemic in years in which
the rainfall is deficient, and the epidemics are on the largest scale when
three or more years of deficient rainfall immediately follow each other. .
. . . Conversely, Diphtheria is nearly always at a very low ebb
during excessive rainfall, and is only epidemic during such years
when the disease in the immediately preceding dry years had
obtained a firm hold of the community, and continues to spread
presumably by personal infection." He also avers and proves that
" There are no instances of a succession of wet years in which
Diphtheria was epidemic." Which practically means that a high
subsoil water by locking up the bacillus diphtheria prevents epidemics,
whereas a low subsoil water allows them to escape.
I have carefully compared the Diphtheria returns of Islington
with the rainfall and I find that these statements are practically
borne out. There were some discrepancies noted in the early years
of registration, but these were, I am convinced, entirely due to the
fact that deaths from Diphtheria were in those days frequently
returned as from croup, laryngitis and quinsey. It would take too
long and occupy too great a portion of this report to enter fully
into the question.
It must not, however, be claimed for dry seasons that they are
the sole cause of this disease. "The essential cause," to again
quote from Dr. Newsholme's valuable contribution to the literature
of Diphtheria, " causa causans of diphtheria is the invasion of susceptible
persons by the Klebs-Loeffler bacillus. This does not
exhaust the causation of diphtheria. If we find this bacillus in a
house or town, an epidemic of Diphtheria is not sufficiently
explained. The bacillus may constantly be found in the throats of
sporadic cases of Diphtheria during inter-epidemic periods, and yet
no epidemic arises in these intervals, which are sometimes protracted
over long years. It may also be found in the throats of attendants