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APPENDIX.
INFLUENZA.
REPORT BY THE COUNTY MEDICAL OFFICER OF HEALTH.
The year 1918 stands out as a great influenza year. Account has been given in annual report,s
to the Council 1914-17 of the prevalences in those years of cerebrospinal fever and poliomyelitis which
it was urged, must be regarded as standing in close relation with the comparatively small number of
scattered cases of influenza then occurring; important observations having an intimate bearing upon
this hypothesis have, moreover, been made by Lieut.-Col. Dorgan, in connection with cerebrospinal
fever in army camps ; and more recently Dr. F. G. Crookshank, in his Chadwick lectures and elsewhere,
has studied the close relation to influenza of the Heine-Medin disease. Reference must also be made to
papers by Lieut.-Col. French and his colleagues, on epidemic influenzal "pneumonia" of highly fatal
type, and its relation to "purulent bronchitis." (Lancet, Sept. 8th, 1917 and Jan. 4th, 1919.) It was thus
already surmised prior to 1918 that important developments in regard to influenza might be expected,
but the realisation has in many particulars differed from the anticipation; so true it is that influenza
ever creates the impression of being a "new disease." Sydenham said "if any one ask how he is to
fish out the species" of a particular fever, "let him choose for his field of observation some large and
populous place." Clearly the observer who ventures to describe so complex an "epidemic constitution"
as that of 1918, will be wise if he follow this advice. If London, however, is to be the place selected
it must be realised that the honourable obligation is imposed of striving to keep in view as far as may
be the behaviour there throughout the historical period of the most Protean of diseases ; more in fact
has been written about influenza in London than anywhere else, and it is, therefore, especially
necessary that experience gained there should not be neglected.
It is recorded of one of the earliest influenzas of history, the sweat of 1485, that it killed two
successive Lord Mayors and four Aldermen; again, the mortality per 1,000 of population in the sweat of
1551 is fairly accurately known, and appears to have been, if anything, somewhat higher than that of
the 1918 prevalence; then there are open for study the classical descriptions by Sydenham of the
influenzas and epidemic agues of the early years of the latter half of the 17th century; and so on down
to the descriptions of the modern pandemic visitations of 1847 and 1890 given by such writers as Drs.
Peacock and Franklin Parsons. For adequate treatment of the subject an "extensive and peculiar"
knowledge, at least of the London influenzas, is to be desired; but any contribution to this will be of
little value if the subject be not approached from the natural history point of view. As Creighton has
said in another connection, the older or Hippocratic method must be applied. This is one which "took
account of gradations, modifications, affinities, being careless of symmetry, of definitions or clear cut
nosological ideas, or the dividing lines of a classification." The attempt to comply with such conditions
will involve reference to the sweats, agues, spotted fevers and lethargies of the early centuries; then,
throughout, to obscure pneumonias, certain outbreaks of "typhus" and various "new diseases";
and finally in the modem period to poliomyelitis, polioencephalitis and cerebrospinal meningitis. Inasmuch,
however, as a large number of detailed studies from special points of view of the problem
presented by the influenzal group of diseases have recently appeared, it is only proposed here to deal
with the broadest aspects of the subject. The report consists of two parts:—
1. A review of recent influenzal prevalences.
2. A study of the light thrown upon these epidemics by earlier prevalences, with a summary
view of the epidemiology of the influenzal group of diseases.
PART I.
The recent influenza prevalences.
Following upon the cerebrospinal fever, poliomyelitis, etc., of 1914-17 (see Annual Reports The first
for those years, and Proc. Roy. Soc. Med. Vols. VIII., X. and XII.) the first indication of the recent beginning
new development was afforded by a rise in the general death rate and in the rates for respiratory diseases
and influenza in the 51st week of 1917, and the maximum number of deaths from bronchitis (283) and influenza
from influenza (16) was attained three weeks later (see Table p. 4). In this first wave of exceptional
mortality, the deaths from bronchitis and pneumonia were notably increased, those from " influenza "
50129 H
The first
beginnings
of the
influenza
of 1918-19
in London.