fortunate in view of the final exchange of straw for coir by the masses of the people-Other infective diseases that will disappear with measles - Tuberculosis - Consumption con- tracted solely in the bedroom-Dr. Emmerich's researches under the floors of rooms-Their important bearing-Views of contagionists and non-contagionists-Koch's theory of the true parasitism of the bacillus of tubercle-Its soundness questioned —It blocks the way to prevention-Consumption easily avoided in the most "consumptive families," but when threatened, or established, the patient may be placed under as favourable conditions in England as anywhere; that is, when wealthy- Prospects of the final release of the poorer classes from con- sumption considered—The bed in consumption—-Soil and con- ditions (heat especially) for the growth of the "true" parasite PAGE INTRODUCTION. LAST year I published "The Prevention of Consumption," and no practical good has come of it. There will not have been one consumptive the less, probably, as a consequence of the simple modes of preventing the disease I ventured to suggest. The whole conception, therefore, has so far been unproductive; but the result was not altogether unexpected. As I foresaw and foreshadowed, the novel views submitted as to the botanical position of the bacillus of tubercle has to bide its time, more especially seeing that it was put forth without giving heed to certain canons and but for the regret one naturally feels that abstract questions of vital interest and pressing concern should be delayed indefinitely for extrinsic reasons, I could be content. One consolation is that the question opened up in regard to the nature of the parasitism of the bacillus is too large to be got rid of by silence or contempt. Whatever may be said, or left unsaid, about it, the true explanation of the causation of consumption is not by any possibility to be had until that question is determined. The issue may be ignored or evaded for a time; but there it is, and there it will remain-until, perhaps, some one among the rising school of pathologists or biologists shall fasten on it and work it out on its merits. Then the conclusions I have formed will, if sound, bear fruit, in spite of having been hung up for a few years: if unsound, they will rightly stay where they are. Yet as I am about to commit further sins in another inquiry into an infective disease, and shall probably repeat them in similar inquiries (for there are several infective disease problems 7. A as yet unsolved), it may be as well to look into the position of those who, like myself, take upon themselves to give shape to their thought on these and kindred questions without being able to contribute original experimental work, and without indeed, any other claim to attention than may reside in the thought itself. It would seem to be the unwritten law in etiology and epidemiology that unless a writer shall be prepared to support his views with microscopical observations of his own, or shall have been at the pains of collecting a certain amount of statistical information bearing upon them, they are to be held to be purely speculative and to be treated accordingly. There may, of course, be other reasons why they should be. shelved, but these omissions of themselves are, apparently, a bar to their receiving consideration from those who do the critical work of the schools in these subjects. Consequently, as my work offered no microscopical or other experimental proof of anything, and was 'not enriched with tabulated statements of facts, all the scientific journals, with the exception of the Lancet, dealt out the law. It was pronounced to be worthless, or was left unnoticed. The Lancet1 did me the honour of quoting my views in a leading article, and reviewed the book in a gracious spirit.2 It was the only organ of the etiological world which truly set forth and gave due prominence to the arguments upon which the questions relating to prevention depend. It stated clearly and concisely the leading contentions of the work-namely, that Koch has erred in his inference that the tubercle bacillus is a "true" or "pure" parasite, and therefore does not vegetate outside the animal organism; and that, as a consequence, this error has rendered his brilliant demonstration of the infective agent in consumption nearly valueless up to the present time: whereas by the inference that the bacillus is an "accidental" parasite vegetating under certain conditions outside the organism, Koch's great discovery is seen to point at once to a ready means for the prevention of the disease-by precluding the occurrence of the specific vegetation on the habitats on which 2 Ibid., October 1, 1887. The Lancet, June 4, 1887. it subsists when it infects man.1 In other scientific reviews these propositions were mutilated by the convenient process of "stating briefly;" or collateral issues and subordinate points only were touched upon. The Lancet, it is true, did not express any opinion upon the soundness or otherwise of the conclusions I arrived at upon the cardinal question as to the bacillus; but that, perhaps, was prudent under the circumstances, and certainly it was quite within the proper exercise of its discretion. The point was novel as well as complex, the evidence produced was purely negative, and further experimental inquiry was demanded before a journal of this stamp could safely commit itself one way or the other: but at all events it gave its readers an opportunity of seeing what the main questions in the book really are, which I take to be one of the primary objects to be aimed at in a review that is to be made in good faith. Coming, however, to minor matters, to which the Lancet reviewer had evidently not given so much attention, I was surprised to learn that the "principles" on which I based some suggestions for the prevention of consumption in persons with the (so-called) "inherited taint," had been "advocated for a long time by physicians, and by none more strenuously of late than Dr. Weber in his Croonian Lectures." In regard to these particular principles I have to observe that, whether they are sound or unsound, I took them to have been at least new. And as the natural influence from the words above quoted is that the method I proposed as new had 1 In part confirmation of my contention that Koch had assumed the pure parasitism of the Bacillus of tubercle on insufficient grounds, De Bary (Lectures on Bacteria, 2nd edit., 1887) observes (p. 153):-"Such observations on the Bacillus itself as have been published, leave much to be desired as regards its morphology." Again at p. 158, he says:- -"The Bacillus of tubercle and Gonococcus may certainly be cultivated as saprophytes, a facultative saprophytism cannot be denied them. But this character can scarcely be taken into consideration in their case; not in that of the Bacillus of tubercle, as Koch urges, because the conditions of its vegetation as a saprophyte are of such a kind, and so limited, that they will scarcely ever be found except in an apparatus contrived for the special purpose." long been known to physicians, and that the rationale of these methods was thoroughly understood by them; as the passage cited would give the impression that, saving the views as to the bacillus, all the rest of the book is a rechauffé of ancient practice and doctrine; and as this tends not only to belittle the nature and scope of my propositions for the prevention of consumption, but to place me in a humiliating or false position (inasmuch as it may be taken to imply that I have put forth ignorantly, or tried to palm off wilfully, other men's thought as my own), I find myself under the necessity of stating that, so far as I can learn, the views contained in the work, whatever they may be worth, are from first to last entirely novel. One cannot be certain perhaps of anything in the way of priority of thought, but I believe it shall not be found that any inquirer had preceded me in the conceptions I formed of the precise cause of consumption (based on Koch's discovery of the bacillus), and. of the practical methods of preventing it. To strip speculative views of their originality is to take away all possible excuse for bringing them out into the light. For if hitherto untouched speculation is barely to be tolerated, the dragging forth of old theories or hypotheses, purposely disguised or innocently naked, is either knavish or foolish. And as one may be acquitted of over-sensitiveness for objecting to lie under either the one or the other imputation, I propose to show that the reviewer in the Lancet fell into a strange error in conceiving that I had simply adopted the "principles." of physicians in general and of Dr. Weber in particular. As the question is one of matter of fact, and may easily be set at rest by any one curious enough to look into the matter, it is palpable that the reviewer misapprehended the argument under review. Therefore one is driven to suppose that, in cursorily running through details, he detected a similarity between the old mode of utilising the solar rays in the treatment of consumption and the new method I submitted of employing the chemical light of the sun for the prevention of the disease, and took these essentially distinct things to be but one and the same thing; and further, that he overlooked the substantial difference there is between |