DEFECTIVE VITALITY-SEPTIC ACTION.

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disease in the other, effective in producing tubercles. In the absence of any direct evidence on this point, we may be guided by certain facts and analogies to the inference that this co-operative cause may exist in the body of the subject, or in the atmosphere, or in both. Where the sarcophytes in the blood and lymph are deficient in vitality, although abundant in quantity, they are more easily injured in their plastic powers by any noxious influence which may affect them; and, proliferating in concrete masses in their adenoid receptacles, form the little tumors, prone to decay, which are called tubercles. On the contrary, where the bioplasm is vigorous and not redundant, it may resist the operation of these noxious influences, and maintain the blood and the lymph in their proper condition for nourishing and invigorating the tissues of the body. The air, too, may convey subtle influences or organisms with septic properties, injurious to life and tending to promote decay; and these may cooperate with the disordering action of any morbid matter previously existing in the body, or introduced into it by inoculation. Take the parallel case of pycemia, or hospital fever. Wounds and suppurating sores of all kinds have little tendency to infect the system, so long as cleanliness and free ventilation carry off decomposing matters, and supply abundance of pure air for the active performance of the processes of respiration and sanguification; but in close habitations, with an atmosphere tainted with foul effluvia, every sore becomes both an inlet and a source of poison, which is spread by proliferating and septic pus-cells throughout the body. This is a rapid and more acute form of cachemia. That inducing tuberculosis is more chronic; probably arising from a less potent septic power in connection with humidity of air, and operating on a less active bioplasm, it palsies and coagulates the lymphatic sarcophytes, which, aggregating

in little nodules, form spots of degenerating and decaying matter in scattered points of the adenoid tissue of the lungs and other organs.

And here we are led to a position from which we may perceive that the local cause of tubercle by inoculation, or by previous existence of either tubercle or some other degenerating matter in the body, is not indispensable. The septic or deteriorating influence of impure air and bad blood may itself be enough to degrade the bioplasm, and engender tubercle, without any additional exciting cause; and thus may arise the constitutional form of pulmonary consumption. Nor are impure and damp air and septichomia the only causes of constitutional phthisis. Insufficient or improper food, bad digestion, malassimilation, venereal excesses, exhausting discharges, and perhaps the secondary effects of febrile poisons, diabetes, and uræmia, have been noticed as antecedents of phthisisoften enough to entitle them to be considered as causes; and it is quite intelligible that they may so injuriously affect the bioplasm as to give parts of it a spontaneous tendency to degeneration and decay. To these must be added family proclivity or hereditary disposition to tubercle. This is regarded more commonly as a predisposing cause, requiring some additional influence, as an exciting cause, to bring it into operation. But some families seem doomed to be cut off by tuberculous disease, which sometimes arises without any obvious exciting cause; and thus tuberculous meningitis in infancy, mesenteric disease in childhood, and pulmonary tubercles in adolescence, attack the members of these families at certain ages, who so fall victims to an inbred decay. Happily, such cases are much more rare than they are reported to have been formerly; and it may be hoped that timely preventive measures, hygienic and medicinal, may still further succeed in averting these untimely tragedies.

ACUTE TUBERCULOSIS.

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It is these spontaneous or sporadic cases of acute tuberculosis which sometimes present characters almost malignant, as if from the presence of poison in the system. Extreme prostration of bodily and mental powers; very frequent pulse; constant pungent heat of the body, often rising five or six degrees above the natural standard; depraved secretions; furred tongue, and sometimes sordes on teeth and lips; occasional low delirium; and rapid wasting of the body,-mark the acute tuberculous fever, in addition to the cough, dyspnoea, and other pulmonary symptoms, and the signs of suffocative bronchitis in all parts of the lung, often masking those of the numerous tubercles scattered through them. Such cases may prove fatal in from two to six weeks, by suffocation or exhaustion, often before there is time for the tubercles to go on to softening and excavation.

The miliary tubercles found in these acute cases are remarkable for their general dispersion over all parts of the lung, not as in the chronic disease, chiefly confined to upper lobes or parts; and also for their plumpness and comparative softness; so that, although they feel as solid granules in the lung texture, they can be crushed by firm pressure, and have not the cartilaginous hardness of older tubercles. They consist almost entirely of aggregations of sarcophytes multiplied in points of the adenoid tissue, with little of the fibrous stroma which time would form around them, and which gives the greater hardness to older tubercles. It may be the soft looseness of these morbid sarcophytes which favours their dispersion and multiplication in these acute cases, even to infecting the whole blood with matter prone to decay. In chronic tubercle, on the contrary, the decaying material is hedged around by tough connective tissue, which limits its dispersion, and in a measure protects the system. We can hardly fail to see here an analogy with the erysipelatous

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.

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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