An Address on CHANGES IN THE CLINICAL ASPECTS OF DISEASE
Authors: H. Rolleston
Journal: BMJ (1927)

CHANGE5 in tllo cliniical characters of disease are interestilng not only to tllose of us who from the passage of time have watched once familiar miialadies alter their features, and become rare, and have seen new ones come on the scene, but to everyone, because differelnt years often show differ- ences in tllo occurrence or the prominence of certain characters and manifestations of the common epidemic diseases.This is particularly true of what wo all, ho;vever muclh we may deplore it in others, are driven sooner or later to call " influenza."In one year it is mainly naso- pharyngeal, in others pulmonary, gastro-intestinal, nervous, or, from the presence of a rash, may imitate scarlet fever, or, as in America in 1923, may be regarded as an epidemic of dengue (vide Hamer, 1923).On the other hand, it might be argued that what are called different types of inifluoeza are in reality distinct diseases, as nmight be suggested by the separation of epidemic or lethargic encephalitis, which at its onset so often simulates influenza.During the war the virulence of influenza underwent a deplorable and dramatic increase in 1918, when there were two waves-tlhe first in the spring wvith a comparatively low incidlence of complications and deaths, and the other in the autumiin, which was associated with Streptococcus haemnolytticus inifectioln and a high percentage of thoracic complications and miortality; this epidemic continued into 1919 and was world-wide.Thus within a short time there was a remarkable change in the-character of a familiar disease, shlowinig that this subject may be of immediate practical importance and not merely of historical initerest.Sydenham maintained that acute diseases showed (1) a long periodic evolution with a rise, decline, and fall extending over centuries; (2) seasonal variations with waves measured in months (as in the influenza of 1918) so that their character and reaction to treatment altered in a short timne, a method successful in one epidemic becoming useless or eveni harmful in another; (3) that there was in hiis rather mysterious " epidemic constitutions " a special influence--telluric, as from the bowels of the earth, or climatic-which becomes dominant and by contaminating the atmosphere and acting on men's bodies disposes them to this or that disease, and impresses some definite character on the clinical manifestations of diseases prevalent at the time to the exclusion of otlher symptoms, the amplitude of this wave being measured in years.Major Greenwood explaiis -the teim " epidemic constitutions" as meaning that secondary infectiouis, such as those familiar in influenza and miieasles, are just as important from the point of view of morbidity :and mortality as the specific causes of disease.Sydenham, of course, had no knowledge of bacteriology, but Sir William Hamer, following in the footsteps of the English Hippocrates, has for years, with attractive eloquience and great ingenuity, argued the epidemiological relationship of diseases associated with different miiicrobic agents-namely, that members of his " ca-tarrllal group of diseases " (influeniza, cerebro-spinal fever, acute poliomyelitis, and encephalitis epidemica) are varianits of the same morbid process; at one time he ascribed them to the same virus acting under different conditions.Referrilng in 1924 to tllese and other acute diseases occurring in " the influcnzal group of diseases," Hanier picturesquely wrote: " Surely we may recognize the l)potean influenza, inow merely in miufti, but changing fromii one civilian garb to another under our eyes, and