pends upon a particular condition of the fluids of the body, the next subject of inquiry is, what that condition may be?

With this view, I must observe, that the animal economy has a singular power of changing acescent aliments, in such a manner, as to render them much more disposed to putrefaction: and although in a living state, they hardly ever proceed to an actually putrid state; yet in man, whose aliment is of a mixed kind, it is pretty certain, that if he were to live entirely upon animal food, without a frequent supply of vegetable aliment, his fluids would advance further towards putrefaction than is consistent with health. This advance towards putrefaction seems to consist in the produc tion and evolution of a saline matter which did not appear in the vegetable aliment, and could not be produced or evolved in it, but by carrying on its fermentation to a putrefactive state. That this saline state is constantly in some measure produced and evolved by the animal process, appears from this, that certain excretions of saline matter are constantly made from the human body, and are therefore presumed necessary to its health.

From all this, it may readily be understood, how the continual use of animal food, especially when already in a putrescent state, without a mix ture of vegetable, may have the effect of carrying the animal process too far, and particularly of producing and evolving a larger proportion of saline

matter. That such a preternatural quantity of saline matter does exist in the blood of scorbutic persons, appears from the state of the iluids above mentioned. It will be a confirmation of all this to observe, that every interruption of perspiration, that is, the retention of saline matter, contributes to the production of scurvy; and this interruption is especially owing to the application of cold, or to whatever else weakens the force of the circulation, such as the neglect or want of exercise, fatigue, and despondency of the mind. It deserves indeed to be remarked here, that one of the first effects of the scurvy once induced, is very soon to occasion a great debility of the system, which occasions of course, a more rapid progress of the disease. How the state of the fluids may induce such a debility is not well understood; but that it does depend upon such a state of the fluids, is rendered sufficiently presumable, from what has been said above with regard to both the causes and the cure of scurvy.

1813. It is possible that this debility may have a great share in producing several of the phenomena of scurvy; but a preternaturally saline, and consequently dissolved, state of the blood, will account for them with more probability: and I do not think it necessary to persons who, are at all accustomed to reason upon the animal economy, to explain this matter more fully. I have only to add, that

if my opinion in supposing the proximate cause of scurvy to be a preternaturally saline state of the blood, be at all founded, it will be sufficiently ob vious, that the throwing into the body along with the aliment an unusual quantity of salt, may have a great share in producing the disease. Even supposing such salt to suffer no change in the animal body, the effect of it may be considerable; and this will be rendered still more probable, if it may be presumed, that all neutral salts, consisting of a fixed alkali, are changed in the animal body into an ammoniacal salt; which I apprehend to be that especially prevailing in scurvy. If I be at all right in concluding, that meats, from being salted, con tribute to the production of scurvy, it will readily appear, how dangerous it may be to admit the conclusion from another theory, that they are perfect, ly innocent,

1814. Having thus endeavoured to explain what. relates to the cure of scurvy in general, I judge it proper to leave to other authors, what relates to the management of those symptoms which require a particular treatment.

CHAP. IV.

OF JAUNDICE.

1815. I HAVE here passed over several of the titles in my nosology, because they are diseases not of this island. In these, therefore, I have no experience; and without that, the compiling from other writers is always extremely fallacious. For these reasons I omit them; and shall now only offer some remarks upon the subject of jaundice, the last in order that I can possibly introduce in my course of Lectures.. :

1816. The jaundice consists in a yellow colour of the skin over the whole body, and particularly of the adnata of the eyes. This yellow colour may occur from different causes; but in the jaundice, hereafter to be more exactly characterized, I judge it to depend upon a quantity of bile present in the mass of blood; and which, thrown out upon the surface, gives its own proper colour to the skin and eyes.

1817. That the disease depends upon this, we know particularly and certainly from the causes by which it is produced. In order to explain these, I must observe, that bile does not exist in its pro

per form in the mass of blood, and cannot appear in this form till it has passed the secretory organ of the liver. The bile therefore cannot appear in the mass of blood, or upon the surface of the body, that is, produce jaundice from any interruption of its secretion; and accordingly, if jaundice does appear, it must be in consequence of the bile, after it had been secerned, being again taken into the blood-vessels.

This may happen in two ways; either by an interruption of its excretion, that is, of its passage into the duodenum, which, by accumulating it in the biliary vessels, may give occasion to its passing again into the blood-vessels; or it may pass into these, by its being absorbed from the alimentary canal, when it happens to be accumulated there in an unusual quantity. How far the latter cause can take place, or in what circumstances it does occur, I cannot clearly ascertain, and I apprehend that jaundice is seldom produced in that manner,

1818. The former cause of stopped excretion may be understood more clearly; and we have very certain proof of its being the ordinary, and indeed almost the universal cause of this disease. Upon this subject it will be obvious, that the interrupted excretion of the bile must depend upon an obstruction of the ductus communis choledochus: the most common cause of which is a biliary concretion formed in the gall-bladder, and from thence