INFLUENZA.*

IT would obviously be unwise not to pay close attention to the views of a man who can justly claim that he publicly foretold

a pestilence a year before it arrived, even if we should find that these views run counter to the opinions of apparently great authorities in whom we have heretofore placed implicit confidence. When, therefore, Dr. Crookshank—who, in 1917, a year before the great influenza pandemic, publicly announced

the coming of the pestilence—takes up his pen to write about influenza., the reader may be quite sure that his essay will repay close scrutiny, even though the reader be not already acquainted with the excellence of form and the brilliance of the logic of the author's previous writings. The book is not easy reading. There is something rather unusual, rather baffling, in the outflow of words which, like a flood, threaten to overwhelm the reader should he allow his attention to stray even for a moment. But ce one proceeds there follows a feeling of exhilaration, a delight in the mastery of words, in the sharp thrusts that the writer

makes at his opponents. Here is no ordinary medical writer setting physics against metaphysics, but one holding that metaphysics is of fundamental importance in science, as his approval of a quotation from Professor Wildon Carr shows :-

"Modern science is the result of the formulation and adoption of the experimental method, but tho experimental method is not self-evident or inherently rational ; it depends on a meta- physical concept, and its rationality can be established only by metaphysical principles."

If Dr. Crookshank has a fondness for rather unusual words

such as " discerptible," they are to be found in any good English dictionary, and hybrid Graeco-Latin words, such as mar the efforts of many medical writers, are not introduced into his writings. But we must protest against his numerous untrans- lated quotations from French writers. It is, indeed, asking too much of the Entente. The argument that only thus can be conveyed to the reader the finer shades of meaning of the author quoted can only apply in the case of such readers as are well acquainted with French. Surely the number who would be helped by a good translation is much larger, especially when the quotations such as those from Rabelais are in the French of the Renaissance. Moreover, if this form of quotation is neces- sary for one language, it is necessary for all. Dr. Crookshank's quotations in their own language are, however, almost entirely from French writers, whose genius he has always admired as much as he is inclined to depreciate the genius of the modern Germans. While acquitting the writer of any specious tendeney

to follow a post-War fashion, one wonders whether he is as good an interpreter of German thought as he undoubtedly is of a certain school of French thought.

Dr . Crookshank's essays fill a third of the volume which he has edited, and contribute much more to our understanding of influenza than do the other essays, excellent as these are. Constantly throughout Dr. Crookshank's essays we seem to be following a will-o'-the-wisp, the question " What is

influenza ? " To arrive at an answer we are asked to follow

the writer in some hard thinking and to shed many of our pre- conceived and cherished notions. The disease influenza, as the essayist is at much pains to point out, is no definite entity to be placed in a phial in a laboratory, but is, to quote Mercier, " a

mental construct : the idea of a symptom or group of symptoms, correlated with or by a single intra-corporeal cause, known or postulated." We are not certain that the distinguished editor, if his remarks are intended for his medical brethren, is not here flogging a dead horse, but, on the other hand, the view which is deprecated certainly survives among the general public, who do expect their doctors to be familiar with diseases of various kinds, " in the manner of schoolboys who spot a

coin or postage stamp and duly label it after consulting a catalogue and pictures."

Again, influenza is no new disease, although one finds, tracing it through the centuries, that on its appearance it has been

constantly hailed as such. Hamer, Creighton, Crookshank and others have, as the result of their studies of the European pestilences of the last 500 years, concluded that these outbreaks of sweating sickness, epidemic " dengue," " malaria," and so on, were pandemics of influenza due to the same cause or causes as the recent outbreaks of influenza in 1889-90 and 1918-19, although frequently attributed as were the earlier cases of 1918 to the ingestion of some article of food—we can all remember

• Influenza. Essays by Several Authors. Edited by F. G. Crookabank, M.D. (Load.). F.B.C.P. London : Heinemann (Medical Books), Ltd. pOs. net.)

the cases of " botulism " or " sausage-sickness " about which medical men and the public were so perturbed, the very cases which Dr. Crookshank recognized as the forerunners of an approaching influenza pandemic. Such pandemics recur every thirty years or so, and are always preceded and followed by just such typical nervous and other cases as have been observed during the recent wave of influenza. These pandemic waves, the author maintains, are the consequence of an " epidemic constitution," i.e., of the world, due probably to world-wide telluric or even cosmic influences affecting all living creatures, from insects to man. Cosmic influences ! The very suggestion is apt to make many scientists smile; but, undismayed, the writer proceeds on his way and turns the laugh against them. According to this concept of an epidemic constitution during what one may speak of epidemiologically as the quiescent period, the 'recognized specific forms of disease are observed, which after a certain space of time give place to " a generalized form recognized as classical influenza," and then revert to the specific forms. Dr. Crookshank would not describe cases as " influenza," however clinically they may correspond with cases of influenza seen during the pandemic, which may be observed in the intermediate period. Dr. Hamer, who shares the editor's views about an " epidemic constitution," does not seem in his essay on " The Phases of Influenza " to agree with Dr. Crook- shank on this last matter, or with his views as to the spread of the disease without contact.

So much has been heard about the so-called influenza bacillus (Pfeiffer's bacillus) that it will be a shock to the lay mind to learn that there is considerable doubt as to its being of more than very secondary bacteriological importance in the' production of the disease. Dr. Donaldson is really quite disrespectful to it, and apparently with good reason, but even in this volume some of the essayists break a lance for the diminutive creature and certainly succeed in shaking some of Dr. Donaldson's arguments. But the whole subject bristles with difficulties, epidemiological, clinical and bacteriological, so that the reader expecting something definite may be a little disappointed, though the book will undoubtedly advance the study of this recurrent scourge.