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Dr. Greenwood goes on to show how it at length became clear that the statistical method was of value
in epidemiology; but, he says, "the developments of the two scientific methods—that of statistics
and that of clinical field observation—were not co-ordinated for centuries." He contrasts the outlook
of the "systematists" of the 18th century with that of latter day workers with the Petri dish and oil
immersion lens; and he notes that there have been two great waves of progress, one in the first fifty
years of Queen Victoria's reign, and one brought about by the events of the great war; in both instances
the advance resulted from appreciation of the need for the closer co-operation of isolated investigators.
It must be remembered that the exigencies of war, with their demand for immediate action, led to
employment of snapshot diagnoses—P.U.O. (Pyrexia of uncertain origin), D.A.H. (disordered action
of the heart, and N.Y.D. (not yet diagnosed)—to an extent which would have greatly perplexed the
systematists ; and, then, partly as the outcome of the hesitancy thus engendered, and partly as a result
of the fact that the new army bacteriologists were not merely laboratory recluses but field workers
as well, there has grown up a disposition to look critically at the whole question of diagnosis, and to
realise that, as Dr. Gee used to say, "medicine consists of three parts, the first is diagnosis, and the
second is diagnosis, and the third is diagnosis." With all this, it has become apparent, perhaps even
to the beginner, that from the pre-war point of view it is not possible to explain everything quite
satisfactorily.
That a new spirit was abroad was already evident, in 1915, at the meetings attended largely by
R.A.M.C. officers in the rooms of the Royal Society of Medicine. In 1916, Col. Dorgan's report, which
broke entirely new ground, on the epidemic at Garrison X, was written. The height of Garrison X
above ordnance datum is not given, but it clearly afforded vantage ground sufficient for taking the
long view. Early in 1919, in his Goulstonian Lectures, Dr. W. W. C. Topley gave from his bacteriological
Pisgah further glimpses of the promised land. Dr. Crookshank in his lectures and papers may be truly
said to have roamed at large in the new territory. In a recent address (Roy. Soc. Med. Vol. XIII. 4), he
considered " First Principles ; and Epidemiology," telling us that " to diagnose an epidemic one must
collate cases in a community, whilst to diagnose a disease one had only to collate symptoms in an individual.
Hence the well known varied and inconsistent character of diseases when they become epidemic.
Epidemics are necessary for the realization of the pathological unity of diverse symptom groups due
to the same exogenous virus One, by 'influenza,' means the disease; another, the
epidemic; and some of us have in mind rather a vast, heterogeneous, unstable, differentiated and composite
pestilence In a typical epidemic of influenza there are cases which appear nervous,
others which are respiratory, others which are gastro-intestinal. In atypical epidemics the cases are
mostly nervous, respiratory, or gastro-intestinal. But in the major prevalences, extending through a
term of months, or even years, there are groups of lesser prevalences that appear as essential or
autonomous epidemics of nervous, respiratory or gastro-intestinal nature."
And then to quote Dr. Greenwood again," The bacteriological philosophy has 'worked,'it remains
to demonstrate that a truer and more comprehensive epidemiological philosophy will work better still."
He refers to Farr and Simon, "the greatest exponents of the statistical and field methods ....
Farr did not think that epidemiology was but a branch of mathematics; Simon did not look upon it
as a mere blend of unsystematic botany and history. They fully realised that the song was of the
man as well as of the arms; that the conditions of human life—both, as we now say, environmental
and eugenic—were quite as important to the epidemiologist as the ' materies morbi'
The science and art of medicine cannot be developed harmoniously if the epidemiological point of
view is neglected ; there is still much to be learned which only the epidemiological method can teach.
It is our duty to continue the work of those who went before. From the Delectable Mountains the
pilgrims could not indeed gaze steadfastly through the ' perspective glass 'towards the city, but yet
' they thought they saw something like the gate and also some of the glory of the place.' "
A.—Vital Statistics.
The population of London County at the census of 3rd April, 1911, was 4,521,685, and it was
estimated by the Registrar-General to have declined to 4,518,021 in the middle of 1914. Estimates of
the civil population have been made by the Registrar-General since 1914 based upon the National
Register of August, 1915, supplemented by information obtained in connection with the rationing of
food. The civil population of London, thus estimated, was, in the middle of 1919, 4,358,309, an
increase upon the corresponding estimate for 1918 of 403,755.
The total population of London, similarly estimated, amounted to 4,540,062; this represents
the present population of London, plus Londoners still on active service. Hence were demobilisation
complete the population of London would number about 20,000 more than in 1914.
The Registrar-General's estimate for 1914 is probably too low. There is reason for thinking in
fact that the population increased between the date of the census and the commencement of the war ;
for building activity in outer London had already begun to decline before the census, and as a consequence
the outward movement of preceding years was falling off between 1911 and 1914. As a result
the number of children scheduled for elementary education which, up to the time of the census, had
steadily declined, began to increase, so that in 1915 the total scheduled actually exceeded the figure for
1901. The increase in scheduled children between the census of 1911 and the middle of 1914 amounted
to over 16,000, and this probably means a considerably greater increase in the total population : thus
the total population in 1914 must have been about the same as the Registrar-General's estimate for 1919,
viz. 4,540,062. Of this number, however, over 80,000 were still on active service, so that actually at
the middle of 1919 the resident population of the county was, if the food registration figures be taken as
55580
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