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it, we must duly keep in view all the elements concerned in its production, and give full consideration to the variations which these may occasion in individual cases. This subject will require reconsideration under the head of Treatment: when I hope to prove that the view here taken of the nature and causes of pulmonary consumption will receive new confirmation from the facts best ascertained with regard to its prevention and cure.
FAMILY PREDISPOSITION AND CERTAIN OTIIEB CAUSES OP
Causes, general and local—Family Predisposition—Consumption proved to he hereditary—Opinions of Niemeyer, Virchow, and Waldenburg—Family Predisposition explained—Hereditary Tuberculosis in Sheep, Cattle, and Guinea-pigs—Offspring of Gouty, Syphilitic, Aged, and Asthmatic Parents often Consumptive—Prevalence of Family Predisposition—Evidence of Louis, Copland, Cotton, Fuller, Pollock, Briquet, and the Author—Its more frequent occurrence among Females than Males—Paternal and Maternal Transmission—Influence on age of Attack—Private and Hospital Practice —Influence on Symptoms—Cases—Influence on Duration—Relations affected—Age at Death—Conclusions—Other Causes of ConsumptionImpure Air and Improper Food—Continued Fevers—Scarlatina and Measles—Cessation of Discharges—Unfavorable Confinements and overlactation—Mental Depression—Damp—Buchanan and Bowditch's Researches—Dusty Occupations—Consumption not infectious.
Some of the causes of consumption have been glanced at in the preceding chapters in their pathological relations: in this we propose to discuss some of the more important ones which have not yet been considered. Looking at the subject broadly, the causes may be classed as follows, as :—
1. General causes, which, by their weakening influence on the constitution generally, predispose to consumption: such are family predisposition, want of pure air and good food, continued fevers, scarlatina, measles, cessation of discharges, miscarriages, bad confinements, and over-lactation, mental depression, dampness of habitation.
2. Local causes, the effects of which are limited at first to the lungs, but may at a later date extend to the system. These are: attacks of bronchitis, hooping-cough, and croup; attacks of pleurisy and pneumonia; attacks of asthma; trades and occupations giving rise to a dusty or gritty atmosphere; injuries.
Such are the principal causes of pulmonary consumption; and they may act either as predisposing or exciting causes of the disease. Insufficient food and severe fevers, by impoverishing the blood, and interfering with the nutrition of the body, may predispose to consumption. On the other hand, in a case of well-marked family predisposition, they may excite the hitherto latent malady. Some of the local causes may act as directly exciting causes, by giving rise to irritation and a low form of inflammation, the products of which would tend to disintegration.
Family predisposition has by general consent held a very prominent place, but the value of its influence in the causation of phthisis has been modified of late years by the fuller recognition of other causes which had been to some extent overlooked—such as damp, inflammatory attacks, &c. These and other direct sources of phthisis must exercise in our calculations a depreciatory influence on the amount we assign to hereditary transmission, and numerous cases of this disease which have hitherto been held to originate in a consumptive ancestry, will now be traced to a nearer and more direct cause. Nevertheless, no small number of cases owe their origin to hereditary predisposition and to no other cause, though it is not always easy to demonstrate their hereditary character. Its exact value as a predisposing agent, its mode of transmission, the varieties of the disease in which its influence is most apparent, all these and other points of interest are by no means settled questions, but still open to further enquiry.
One of the most striking proofs of the hereditary FAMILY PREDISPOSITION.
character of phthisis is the presence of tubercles, often demonstrated in the lungs of a foetus or of a young infant1 of consumptive parents; another, though less striking one, is to be found in instances where a consumptive and healthy person marry, and the children become consumptive; but, on the death of the affected parent, the sound one marries again and the offspring of the second marriage is healthy.
Niemeyer admits that the tendency to consumption is inherited only if the parents were consumptive at the time of begetting the offspring. 'But it is not,' he says, 'the malady which causes inheritance, but the weakness and vulnerability of constitution, which had already laid the foundation of the consumption in the parents, or which had arisen in them in consequence of that disease.'2 Waldenburg3 denies the direct hereditariness of consumption by means of a specific contagion, and only allows, in any case, the transmission of the phthisical habitus and innate disposition of the parents to phthisis. Both these authors, regarding tuberculosis as a secondary product, and never a primary one, hold that tubercular consumption can never be directly inherited, but that the caseous deposits from which it arises may be produced by the scrofulous or phthisical habitus.
1 Waldenburg and Virehow deny this as regards miliary tubercle. We would draw their attention and that of our readers to the following passage in Sir Charles Scudamore's work on Pulmonary Consumption, p. 55:— 'I examined the body of an infant which died of extreme emaciation at the age of four months, the mother having been in the last stage of tubercular phthisis when she gave birth to it. I never witnessed so remarkable and extensive a display of tubercles, both miliary and of a larger size, the former scmitransparent, the latter grey in colour. The lungs on each side, both upper and lower lobes, the liver and spleen, the mesentery and peritoneum, were universally studded with tubercles.' The italies are our own, but the description needs no comment.
1 Text-Book of Practical Medicine, vol. i. p. 213.
* Die TulierciUose die Lungenschwindswht und Scrofulose,' p. 524.
Waldenburg citos an instance of six brothers and sisters, who, when they
We propose to consider some of the principal features of the subject, and to give, as concisely as possible, the conclusions which our researches and those of others warrant us in adopting; aud first, we would explain why we prefix as the heading, 'family predisposition,' instead of 'hereditary predisposition.' As it was our object to work on a broad basis, it was thought desirable to estimate indirect as well as direct influence, and for this purpose the existence of consumption was noted in uncles, aunts, brothers, and sisters, as well as in parents and grand-parents, the principle being to accept as instances of disease in the family all those derivable from a common stock. Several phthisical uncles and aunts throw a suspicion of consumptive taint on the grand-parents, while several brothers and sisters thus affected would lead us to suspect, though not necessarily to conclude, that the parent's health was not quite sound.
It may, however, be objected, that the fact of several of the same generation being affected may be explained by a local cause; for instance, a healthy married couple may take up their residence on a clay soil, and their children born and bred in this unhealthy locality may be attacked one after another with consumption. In this instance it would be clearly incorrect to attribute the
first came under his notice were strong and blooming, but five out of the six died of phthisis between the ages of 2-i and 34, the disease beginning in many of them with haemoptysis. The fathor died of a different complaint, and the mother, up to the age of 53, enjoyed uncommonly good health, being quite free from any symptoms of consumption. She was then suddenly attacked with haemoptysis, and expired the same day, her death being subsequent to the commencement of the disease in the children. Waldenburg says the children's ill-health could not be traced to endemic causes, as they had lived in different localities, and soparated from each other, and had been brought up under favorable circumstances. He concludes, ' This is a very remarkable instance where the mother, without having phthisis herself, had the disposition to consumption, and transmitted it to the children, who died of phthisis.'