The Lumleian Lectures on the Aetiology of Phthisis
Authors: J. Andrew
Journal: BMJ (1884)

LECTURE III.IT was my intention to have dealt separately with the evidence as to the contagiousness of phthisis, and with its analogy in many re- spects to malarial fever; but the two diseases are so closely related, each throws so much light upon the other, in respect to the question of contagion, that to do so would involve much nieedless repetition without adding any force to my argument.From our review of the cetiology of phthisis, it is easy to recognise those points in which the two diseases strikingly resemble each other.I shall begin by stating their chief resemblances dogmatically, and without unnecessarily quoting well known facts in their support.Both have been known from the earliest times, and in both the evidence of their having been introduced into any new country by man is very inconclusive.The facts, such as they are, are quite con- sistent with the view that the first discoverers and colonisers of any new country did not, in either case, import some special morbific germ, but found it already there.Both, within historical times, have prevailed in varying degrees in the same locality.Thus, the increase of phthisis in America and in Australia is fairly comparable to that of malarial fever in Italy.In each case a change, more or less complete, in the race of the inhabi- tants of the country, with in the first case an advancing, and in the second with a retrograding civilisation, seems to have favoured the spread of the specific disease.Both are met with almost everywhere, but phthisis extends somewhat further towards the north than malaria.There is no need to involve human agency to account for this wide dispersal of either one or the other.The same fact obtains in the case of many of the lower forms of vegetable life, e.g., the mosses and lichens.Of these latter several species, common in Britain, have been found in the Falkland Islands, Graham's Land, Kerguelen's Land, and in other antarctic islands or continents; on the Himalayas, in Chili, in Equatorial Brazil and South America, in Spitzbergen, Lapland, Iceland, Nova Zembla, and more northern Polar islands or continents.(Popular History of British Lichens, by Lauder Lindsay, page 97.)In the Transactions of the Linncean Society of London, Botany, Vol. 1, page 391, will also be found a long list of self-fertilising British plants of world-wide distribution.Both, judging by their effects, vary in their characters to a certain degree in lifferent parts of the world ; and thus variation, in the case of malaria certainly, in that of phthisis probably, cannot be altogether due to differences in the personal factors.Compare, e.g., the greater rapidity of the course of phthisis in the tropics, with the greater violence of malarial fevers in the same regions.Both prevail under certain well known climatic and social condi- tions; and yet both are, here and there, unaccountably absent from likely and present in unlikely spots.Both decrease in severity, and finally disappear, with increasing elevation above the sea-level.Both are closely connected with wetness of soil, and both are greatly diminished, if not extirpated, by efficient drainage.Both are sometimes confined locally within very narrow limits; e.g., in malarious countries the second floor of the houses is said to be less dangerous than the first.The action of the micro-organism in each is greatly modified by the personal constitution of those exposed to it.Thus, white races suffer specially from malaria, and negroes from phthisis.In both, a bacillus has been demonstrated, cultivated, and proved by inoculation-experiments to be the exciting cause of the disease.They differ in their habitat, phthisis Being most prevalent in cities which afford all but complete protection against malaria.Clinically, they agree in that recredescence takes place after long periods of apparent health.In the case of ague, this frequently happens without any fresh exposure to infection; and there is often, as in so-called Roman fever, a well marked approach to periodicity in its returns.The history of many cases of phthisis makes it probable that the same thing takes place in it too.