Edgar L. Collis

Tuberculosis and influenza in relation to the world war, 1914-18

Summary The war years, 1914-18, saw the mortality from tuberculosis—a great social barometer—steadily rising, but only in early life. Suddenly, in 1918, came the great influenza epidemic, as a famine pestilence, which struck at the same period of life, previously selected by tuberculosis. Warning should be taken from these occurrences as to what it is reasonable to expect as 1939 passes on to 194?,

The influence of industrialism upon the age incidence of phthisis

Summary No attempt has been made to find evidence in the facts presented in favour of any school of thought in regard to tuberculosis. The object aimed at has been merely to portray the course of events so far as the move of maximum incidence of phthisis mortality in any community is concerned. First, there are primitive communities with no death-rate from the disease; such communities when infected quickly succumb, and probably more or less equally at all ages. What happens in such a community during the time that the disease, from being a new infection, becomes endemic, has not been traced. In a European non-industrialised community wherein the disease is endemic, the age of maximum incidence is found late in life. When the habits and customs of such a community are disturbed by industrialisation, the age of maximum incidence moves to early adult life. As such a community settles down to the new conditions, the age of maximum incidence steadily recedes again to late life. This process may be retarded by such influences as indoor sedentary life, or the alcoholic habit, or may even be reversed by such social upheavals as occurred during the war; it is essentially associated with the industries and is found taking place most rapidly in those occupations which have been least disturbed in recent years. The process appears to occur irrespective of the total phthisis death-rate in the population; it has been slow among agricultural labourers with a low mortality, and among inn-servants with a high mortality; it has proceeded quickly for tailors with a high mortality, and extended furthest among clergy with the lowest mortality of all. In other words, resistance to phthisis in early life seems to depend upon the extent to which the race has suited itself to its environment, while the degree of mortality experienced appears to depend rather on aggregation of population which probably means opportunities for infection.

Tuberculosis: Infection, immunisation, sensitisation*

Summary o (1) Tuberculosis for ages past has been endemic among civilised nations. (2) It is an infectious disease of which the clinical course resembles its epidemiology in being indefinite. (3) In contrast, certain other infectious diseases run a definite course which is held to be terminated because the patient requires an immunity, temporary or permanent. The incidence of these diseases possesses certain definite epidemiological characteristics. (4) Clinical and epidemiological evidence suggests that, in the case of tuberculosis, immunity, such as occurs for other infectious diseases, is difficult to establish. (5) The prevalence of tuberculosis has been steadily diminishing in this country since the early part of last century, during a period in which poverty has been decreasing. (6) Under-feeding is necessarily associated with poverty; and better feeding with a general increase in wealth. Under-feeding has long been held to be an influence predisposing to tuberculosis. The term “under-feeding” possibly means deficiency in some food-accessory factor. (7) Synchronous with the fall in tuberculosis there has been an increase in the amount of milk and of butter consumed per head of the population. (8) If the increase in milk consumption has any connection with the fall in tuberculosis, the result might on theory be due to either of two causes:—(i.) immunisation due to administration in milk of bovine tubercle, or (ii.) an increased supply of one or more food accessory factors, possibly of fatsoluble A. The balance of probability would seem to favour the latter. (9) The possibility of a sufficient supply of fatsoluble A vitamin in food being an influence which increases the power of resisting tuberculosis calls for consideration. (10) Silica is a substance which definitely sensitises the tissues to succumb to tuberculosis. When addressing you 14 last January I dwelt upon the importance of the bio-chemical link in the chain of events which determines one form of tuberculosis. There can be little doubt that somewhere the chain in the causation of tuberculosis in general is weakening; and, in suggesting that this weakening is taking place in the biochemical link, I do not minimise the importance of the other links in the chain. Quite possibly, if the fall in tuberculosis continues and accommodation increases, segregation in sanatoria may provide, as in the case of leprosy in Norway, the assistance needed to bring under control the incidence of the disease which has been falling, due to some other cause or causes; in that case we should be directly controlling the infective organism. Indeed, if Brownlees suggestion that the fall in the disease is largely an epidemiological phenomenon and that a rise must be expected soon—just as sun-spots wax and wane in number—then our only hope would lie in segregation. If, on the other hand, a relation of cause and effect exists between dietetic insufficiency and the disease, we must concentrate on establishing what form that insufficiency takes, and then on supplying the deficiency. In this direction, coupled, possibly, with segregation, there would appear to be great hope.