Massachusetts, that dampness of the soil of any township or locality is intimately connected, and probably as cause and effect, with the prevalence of consumption in that township or locality; and he also adduced particular instances as demonstrating that even some houses may become the foci of consumption, when others but slightly removed from them, but on a drier soil, almost wholly escape. The following instance of this law came under my notice, one of the family being for some years under my care.

The rector of a parish in Essex resides on a clay soil, and has a large pond immediately in the neighbourhood of his rectory. He and his wife have always enjoyed good health, and there is no hereditary disease traceable, either in his own family or his wife's. Of their twelve children, eight were born at the rectory, and four in a neighbouring parish; but all spent childhood and youth at their father's house. The eldest, if alive, would now be 36; the youngest is 19. Six have died; four of consumption, one of scrofulous disease of the spine, and one of hoopingcough at the age of 5. Of the six alive, three are healthy, one is delicate, but I have not heard from what cause; two have scrofulous disease of the spine. The three healthy ones have spent but little time at home since they have grown up, and one spends much time in travelling. So that out of twelve children, there are no less. than four cases of consumption, and three of scrofula.

This seems to me a fair instance of phthisis arising from endemic causes; the social position of the family, who are rich, precluding many other causes, which we have been discussing, from entering into consideration. We may therefore conclude that dampness of soil is an undoubted cause of consumption; and in our preventive treatment of the disease we should aim at either the

drainage of the soil, or removal of the inhabitants to a drier locality.

Of the local causes of consumption, the most important have already been considered, and it only remains for us to notice:

Trades and occupations giving rise to a dusty or gritty atmosphere.-A life pursued in an atmosphere abounding in small particles of flint, or iron, or coal, or cotton, or flax, or straw, as is the case with stonemasons, potters, fork-grinders, needle-grinders, cotton-carders, and chaffcutters, is shown by Dr. Greenhow and others to be a short one: and the cause of death was generally found to be tubercular phthisis, induced by constant inhalation of the irritating particles. These have been detected chemically and microscopically in the lungs. They seem to set up irritation in the larger bronchi, causing thickening; and also in the lung-tissue, causing induration and consolidation. It was at first doubted whether these lesions were tuberculous; but the presence of both gray and yellow tubercle, and the tendency of the consolidations to soften and form cavities, sufficiently demonstrate their consumptive nature. Dr. Greenhow calculated that 45,000 deaths occurred from these causes in England and Wales; and he clearly showed that the whole of this mortality was preventible by the introduction of better methods of ventilation and working. Since his reports, Acts of Parliament have been passed which, if carried out, ought totally to abolish this cause of phthisis; and it is is to be hoped that ere long we may no longer be able to number dusty occupations among our causes of consumption.

6

It may be well, before closing this chapter, to allude to the position occupied by consumption with reference to infection-a subject of very great importance to the community. The idea of the disease being infectious is an

old one, and has always held its ground in Italy. Recently in this country it has been supported by Dr. William Budd,' who holds that tubercle is a true zymotic disease in the same sense as typhoïd, scarlet, and typhus fevers, never originating spontaneously, but perpetuated according to the law of continuous succession; and that the tuberculous matter itself is, or includes, the specific morbid matter of the disease, and constitutes the material by which phthisis is propagated from one person to another and disseminated through society. Among the grounds on which Dr. Budd supports this theory, are (1), the prevalence of both zymotic fevers and phthisis in very crowded communities, and in prisons, convents, and barracks; (2), the geographical distribution of phthisis in past and present times, and its great fatality in countries which when first discovered by Europeans were known to be entirely free from it; (3), instances in which there was evidence to show that the disease was communicated from one person to another.

As regards the first ground, it may be observed that the coincidence of the diseases may be explained by the coexistence of common causes, independent of infection, such as impure air and water, bad food, &c. ; and as to the second statement, if it be well authenticated, it is hardly fair to overlook the change in the habits of natives which contact with Europeans generally entails. This change, as we know well, is generally for the worse; and to a more domesticated life and the abuse of spirituous liquors, much may be ascribed, which Dr. Budd would assign to infection. With reference to the third reason, we must admit that recent experiments on the artificial inoculation of tubercle have given a fresh aspect to the subject of the contagion of phthisis, and have rendered it possible that the caseous and purulent material might infect those

1 Lancet, October 1867.

and phlegmonous modes of pus formation, another phase of sarcophytic history.

If we turn to the external circumstances in which this constitutional form of tubercle occurs, we shall find that, besides damp and foul air, a high temperature seems to favour its production, and in this respect it contrasts with the inflammatory forms of consumptive disease. The latter prevail especially in cold seasons and climates; but consumption is frequent also in hot climates, and often assumes the acute or febrile form, with less marked cough and other pulmonary symptoms. M. Guilbert goes so far as to assert that phthisis increases in frequency from the poles to the equator, and from the highest mountains to the sea-shore. This assertion seems to have been founded chiefly on observations on the South American continent, where the prevalence of the disease in the low, hot plains of Peru and Brazil contrasts strongly with its almost absence in the high table land of Peru and Bolivia, which rises ten thousand feet and upwards above the level of the sea. The climate at this height within the tropics, is much as that of the temperate countries of Europe; and, considering the general prevalence of phthisis in the latter, we must refer the exemption of the mountainous regions rather to their elevation than to their low temperature.

Since the late Dr. Archibald Smith first called attention to the preventive and curative influence of high altitudes on phthisis, his statements have been corroborated by several observers. In Lima, and other of the lower towns of Peru, pulmonary consumption is very prevalent, and it has long been the practice to send invalids up the Andes, to altitudes of from 8,000 to 10,000 feet, and with most beneficial results. Dr. Guilbert gives similar accounts of the efficacy of the high places of Bolivia, and Dr. Jourdanet of the high plateau of Mexico, in preventing

TWOFOLD CAUSATION OF CONSUMPTION.

107

and curing phthisis. In Europe also the greater immunity of high Alpine inhabitants from phthisis has been observed by Lombard, Brehmer, Küchenmeister, and others; and in this country, Dr. Hermann Weber has directed the attention of the profession to the subject in reference to the causation and treatment of phthisis.

The general result of recent statistical observations is that pulmonary consumption is most common in damp, low situations, and those liable to great transitions of temperature, in all climates; that it is of less frequent occurrence in dry places, even although very cold; and that it is still more rare at great altitudes, varying from 10,000 feet in the torrid zone down to 2,000 feet in the cooler temperate regions.

These facts render it most probable that the causation of consumption is two-fold: one class comprising the influences which excite and keep up inflammatory affections of the chest, which end in cacoplastic products, such as transitions of temperature, and prolonged operation of cold and damp; the other class includes septic agencies, which tend to blight or corrupt portions of the bioplasm of the blood or of the lymphatics, and thereby to sow the seeds of decay: these comprise combined warmth and humidity, foul air, bad nourishment, depraving habits or diseases, and the like. And when these two classes of causes co-operate, the effect is more certain; for example, when a person, with bioplasm deteriorated by a foul atmosphere, or by enervating heat, is exposed to a chill, or where the subject of an inflammatory attack is confined in a room tainted with impurities, or deprived of the invigorating influences of pure air, light, and proper food.

It thus becomes manifest that whether we are considering the intimate nature and causation of consumptive disease, or are seeking for means to prevent or cure