PHTFILSIS.
One-seventh of all the deaths throughout the world is due to tuberculosis, and in 13 out of every 14 of these the lungs are affected. It is at once obvious that the prevention and treatment of tuberculosis of the pulmonary organs become the most important problem in practical medicine.
Preventive Measures.—The first advance made in the prophylaxis and therapeutics of phthisis was inaugurated by Henry MacCormac, of Belfast, before the middle of the last century and prior to the original labours in the same direction of Brehmer. MacCormac maintained that phthisis was in eve y single instance preventable by the individual breathing a pure atmosphere, and in his classic work on the " Nature, Treatment and Prevention of Pulmonary Consumption," published in 1855, he laid down clearly the lines which are now universally accepted as the basis of the open-air treatment of tuberculosis. His words may be taken to-day as an epitome of the sanatorium method of treating pulmonary phthisis, which, however, did not come into general practice till nearly half a century later. As a preventive he insisted upon the constant formula to be used by the rich and poor—viz., to sleep with their windows largely open and to spend as much time as possible in the open air. For those already tuberculous he insisted that there should be a ceaseless, unlimited supply day and night, winter and summer, of pure air in the apartment of the sufferer, his rule being that the chamber atmosphere must be as pure and untainted as the open air in which the patient should spend as much time as his strength, the weather, the season and his means will permit. He also emphasised the importance of a liberal supply of highly nutritious food.
The prevention of phthisis has been advanced since the discovery of the causal bacillus, but no measures can be rationally employed in this direc tion unless guided by the knowledge obtained by recent experimental research. The fundamental fact must be recognised that the bacillus of tubercle can be conveyed from the cow to man and from man to man.
Cobbett in his classic work " On the Causes of Tuberculosis " (1917) maintains that when the bovine bacillus attacks man it does not in the course of the disease in any one individual become changed into the bacillus of human type. But if we accept the theory that pulmonary phthisis in the adult is often the result of an intestinal infection in infancy the evidences of stability of type derived from laboratory researches are not conclusive, and the atypical forms found in lupus are regarded by some as evidence of unity of type. The writer, however, accepts Nathan Raw's
view and regards surgical tuberculosis as always of bovine origin, whilst phthisis is almost always caused by the human bacillus. When the bovine bacillus in gland or joint disease invades the blood-stream an acute tuberculosis supervenes in which the lungs will suffer. This, however, does not minimise the importance of the general law. Especially is this distinction of value since it gives the key-note to treatment. All surgical cases (bovine bacillus) must be treated by the tuberculin prepared from the human bacillus, and phthisis must be treated by the bovine tuberculin, as the two types are antagonistic. Without further dwelling upon the nature of the difference between human and bovine tuberculosis it must be recognised that the bacillus is ubiquitous, certainly in cities and probably also in rural districts, and that it is constantly finding its way in minute quantities into the human circulation by various channels.
Under ordinary circumstances the defensive mechanism of the human body is quite sufficient to deal with these stragglers, but once this natural resistance has become broken down by illness of any kind, by the constant breathing of impure air, starvation or even by local trauma, the bacillus is enabled to increase and multiply itself.
The natural resistance, or, in other words, the defensive mechanism, being weak in many individuals owing to hereditary or congenital causes, these succumb to phthisis or other form of tuberculosis when their companions, submitted to the same environment, remain healthy. Hence the necessity of open-air life and good feeding as a preventive in all in dividuals whose family history shows numerous examples of tuberculosis, Probably no person is immune to the bacillus, whether this be of the human or bovine variety, if the organisms gain admission to the body in such numbers as cannot be effectually dealt with by the natural defensive mechanism. The question of infection therefore resolves itself practically into that of the dosage of the living virus.* In order to rationally carry out a successful preventive treatment it is necessary to recognise the channels by which the bacillus finds its way into the human organism.