PHTHISIS (a Greek word, epefair, signifying "corruption," " decay") was formerly used as a generic term to signify a wasting or consumption from any cause, and was afterwards more distinctly specified, according to the organ in which it was supposed to originate: hence we had a Phthisis hepatica, P. mesenterica, P. pulmcludis, &c.; but the word is now restricted to the disease produced by tubercles in the lungs, and commonly known by the name of consumption. An acquaintance with this disease, from which neither age nor sex is exempt, and no part of the habitable globe is free, whose ravages extend even to the brute creation, and whose course when once begun can rarely be stayed, whose commencement is frequently so insidious, and whose termination so fatal, must, above all others, be interesting; for if by any precaution its development can be prevented, it is only by a know ledge of those influences which most frequently give rise to it that we can hope to attain our object.
Morbid Anatomy of Phthisis.—The local morbid changes peculiar to phthisis are only the result of previous changes in the general system, II an hereditary or acquired predisposition, cognisable by the physical condition of the patient, and by a state of various functions, " and which, though very generally accompanied with a feeble organb seism, is not itimmeistent with too great development and inordinate action of particular parts, and even with considerable physical power of the system." By far the most important and characteristic morbid change that occurs in phthisis consist. in the development of tubereles wherever they may be found; but as it is In the lungs that they first and most frequently manifest themselves, we shall describe them as they are teen In thee. organs. Tubercles of the lungs first appear In the form of small, gray, semi-traneparent granulations, which gradually enlarge and become opaque in their centre : the opacity increases, till the whole meal becomes of a dull yellowish-white colour. After a certain time they soften, empty themselves into the bronchial tubes, and glee rise to excavations more or less considerable. In this way, almost the whole of both lungs may be Invaded by a succession of tubercles, their heelthy structure being absorbed as the tubercles become deposited, or involved in the deetructive process consequent upon their softening. Tubercle*, milike inflammation, almost inva riably commence at the summit of the lungs, where, as well as being more numerous, they are usually found in a more advanced stage of development than In any other pert. The successive eruption of fresh
tubercles is an important feature in this disease, as it explains the occasional recovery of patients labouring under consumption. A crop of tubercles may appear in the lunge, go through the various stages above give rise to all the symptoms of confirmed phthiais; yet, provided the conditions which gave rise to them are removed, no fresh eruption may take place, and the patient may recover. The relative frequency of tubercles in other organs differs considerably in the adult and in the Infant. In the former, 31. Louis, our greatest authority in all matters connected with phthisis, has, with one exception, never observed them in any organ without their existing in the lungs; so that he regards their presence in these last viscera as a necessary condition for their development In other parts. But in the infant this does not appear to hold good ; the bronchial glands being more frequently affected than the lungs, in the proportion of 87 to 73. The brain and its membranes are likewise more eubjcct to teiberenlous deposits in tho child than iu the adult. The next most important lesion which is met with in viable's is ulceration of the intestinal canal. The ulcers may vary in number, form, and size; but they all present Teeltic characters peculiar to this disease, and exist in firealethe of the eases which terminate fatally. The third peculiarity in reference to phtldsis Is the change which the liver undergoes, to which the French pathologists have given the name of foie graft, or fatty liver. Lastly, ulcerations of the epiglottis, larynx, and trachea occur so frequently, and with such uniformity of type, as justly to load to the belief that they are a part of the disease. But besides these morbid changes, which are peculiar to this disease, complications of various kinds occur which are common to it and other chronic diseases. By far the most frequent of these are inflammations of the pleurae; so that it is extremely rare, in making the post mortem exami nations of persons who die of phthisie, not to find the lungs adherent, in pert or entirely, to the walls of the chest. Inflammation of the substance of the lungs is likewise a frequent complication In the latter stages of phthiais.