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15
connection with prevalences of influenza." Dr. Boiret is reported by Dr. Low to have made a similar
observation in 1909. This broadening of the point of view despite the tendency with the advance of
bacteriology to limit cases to those possessing particular bacteriological features, led to great increase
in the number of reported cases and the facto cannot be given in the same detail as for the years preceding
1890. On a wide survey, however, it may be said that after increase, at the time of and immediately
succeeding the pandemic prevalence of influenza and after prevailing to a lessening ext nt in conjunction
with tra'ling epidemics of influenza, or as at Trefail in Styria in 1898, as a "pseudo-influenza," there
then supervened marked diminution; after a time increased diffusion of cerebrospinal fever again
followed as in New York State in 1904, in England, France, Germany, Italy, etc., as early as 1905,
in Glasgow and Belfast in 1906-07; and then later, about 1912, a ma:ked increase developed throughout
the civilised world. During the first half of 1914 cerebrospinal fever was reported to be present in
Moscow, for some years past, too, there has been repeated mention of poliomyelitis in various parts
of Europe and America. (Brorstrom's book on the latter disease dates from 1910)
In summary, taking into account, so far as may be, variations of fashion as regards nomenclature,
there seems to have been round about the time of the great pandemic influenza, increased morta ity
from cerebrospinal fever (and, it may be added, from poliomyelitis also) from some five or more years
before to some five or more years after 1890; in the same way, for five or more years prior to the
explosion of 1918 there was again a growing diffusion of both cerebrospinal fever and poliomyelitis,
There has thus been an overlapping of outbreaks of cerebrospinal fever and poliomyelitis with the
great preva ences of influenza. The former precede and lead up, as it were, to the pandemic prevalence;
with the establishment of this, cerebrospinal fever and poliomyelitis fall into the background, but then
again later come to the fore as successive "trailers" follow the great prevalence; five or more years
after the pandemic they revert again to comparatively speaking insignificant proportions.
There seems, therefore, to be discernible for thickly inhabited areas of the globe, a kind of law
of coincidence or of overlapping between cerebrospinal fever and poliomyelitis and pandemic influenza.
It was pointed out elsewhere three years ago (Proc. Roy. Soc. Med., Vol. X.) that the special years
of cerebrospinal prevalence recorded by Hirsch, commenced three or four years after each pandemic
influenza prevalence. A closer analysis of Hirsch's data shows, however, that the great influenza pandemics
of the nineteenth century were both introduced, and followed after a few years, by cerebrospinal
fever prevalences; in fact, each of Hirsch's four groups of years comprises an earlier series following
a precedent influenza pandemic, and a later series leading up to the next following influenza pandemic;
there is thus noticeable as a rule, a gap in the middle of each of his groups of years and this is particularly
apparent in the middle of his second period. Thus, for example, in France, it is recorded in 1842
that "the succession of epidemics comes to an end." and it is not until 1846-50 that there are further
references to extensive epidemics; in the United States, epidemics are only reported towards the close
of Hirsch's second period. Again, as regards the middle of his third period it is notable that Sweden
shows considerable decline after 1859; moreover, the south and west of Europe escape during the same
series of years and until the approach of the next pandemic. Following upon the 1873-74 pandemic
there was, however, a somewhat abrupt cessation of cerebrospinal fever in the United States. Moreover,
as already stated, in that country there were no recorded prevalences between 1816 and 1842;
thus the period round about the 1833 influenza pandemic was not productive of records of cerebrospinal
fever in the western hemisphere; it is deserving of note that that hemisphere seems to have had an
influenza of its own about 1815-16, and it may be that this accounts for its escaping quite lightly in the
pandemic of 1833 and onwards; similarly in 1873-74 the western hemisphere again suffered disproportionately,
and in correspondence with this was for a time quite clear from both influenza and cerebrospinal
fever.
It will be seen then, that the facts elicited on study of the relationship between influenza and
cerebrospinal fever in the recent prevalences, or within the period of notification statistics, or on a wider
view within that covered by Hirsch's chronologies, are strikingly confirmed, if in some measure also
modified and corrected, on taking a broader sweep still and pursuing enquiry, by means of the great
storehouse of facts collected by Creighton, into the history during the last five centuries of the influenzas
and cerebrospinal fevers, etc., which lurk more or less disguised under such designations as sweats,
agues, cerebritis, encephalitis and typhus (cerebralis or other).
As Creighton has observed, influenza can be "identified as certainly in the brief phrases of mediaeval
chronicles as in elaborate modem descriptions"; by his careful analysis of the facts he has, moreover,
securely established the close relationship between epidemics of influenza and epidemics of ague; it
is now, moreover, claimed that these remarkable related agues consisted of the fevers with gastrointestinal,
pulmonary or nervous complications, which are becoming recognised as constituting the
disease types the Proteus influenza is apt to assume. Attention has been more especially devoted in
the present enquiry to cerebrospinal fever, because it has been possible to pick out the epidemics of this
disease, like blackberries from a bush, in Creighton's great historical chapter on typhus and the continued
fevers. A similar harvest has, however, been collected by Dr. Crookshank from the literature of the
Heine Medin disease, and had materials relating to epidemic pneumonias or epidemic bronchitis been in
like manner available, this field of enquiry could also doubtless have been exploited with profit.
Two further points may be now mentioned. First—It should be realised that influenza pandemics
did not in the nineteenth century affect all parts of the civilised world simultaneously, there was, indeed,
a tendency to alternate between the eastern and western hemispheres (Europe suffering more in 1780-82,
America more in 1798-99, Europe about 1800, America almost exclusively in 1815-16 and again in
1826-27, Europe much more about 1830, America early in the forties, Europe later in the forties, America
in the fifties, and again in the late sixties and early seventies; both, however, were involved to a
Summary
view of an
" influenzal
constitution,"
i.e., of
the development
during
a series of
years of
various
types of
epidemic
prevalence
round and
about the of
occurrence
of pandemic
influenza.