persons dead men's flesh. The oyster, which belongs to another class of animals, called mollusca, breathes by means of that part which resembles a fringe, and is called the beard; whilst in the true fish, such as the herring and the shark, we find for the same purpose, those parts which are generally known by the name of gills; but even in these there is some variety. On the other hand, those animals which either live in air, or at least breathe it, are provided with lungs, or with organs bearing some resemblance to them. The snail, which I mention as a specimen of the soft animals, or mollusca living in air, has a kind of lung. The caterpillar, and the animals allied to it, of the insect class, are furnished with two tubes, one on each side of the body, for the reception of air, which finds its way into and out of them by two corresponding rows of small pipes or pores called stigmata. Frogs, turtles, serpents, and other reptiles, have regular lungs, but of a coarse texture; birds breathe by means of lungs of a fine texture, which have as accessories various large cavities, which receive air from the lungs.

"Man, as you know, and those animals which belong to the same class with him, breathe by means of very perfect lungs, which occupy a considerable part of the trunk. The air enters them by the windpipe; this divides, and its branches again and again divide and subdivide, till its small and delicate branches have conveyed the air into the soft and spongy structure of the lung, in which it is brought into intimate contact with the organ. In man, and in those animals which resemble him in their mode of breathing, the process of respiration is partly mechanical and partly chemical.

"The mechanical parts consists in the admission of air by the expansion of the cavity, which is brought about by the raising of the ribs, and the descent of the diaphragm or midriff, and in the expulsion of the air when the capacity of the chest is diminished by the falling of the ribs and the raising of the diaphragm. In its passage between the mouth and lungs the air may be stopped at a narrow part, a little behind the tongue, called the rima glottidis. This may happen at our own will, or at times by serious or even fatal accident. The air, as it is put in motion in the lungs, by the act of taking in and sending out breath, produces a sound which may be heard through the ribs, and which differs in the healthy and the diseased states of the lung. On this fact is founded the use of the cylinder or stethoscope, an instrument of great advantage in the investigation of the diseases of the chest.

"The chemical part of the process consists chiefly in the loss of oxygen gas, and the formation of carbonic acid gas: the one is generally equal to the other. There is, however, some difference in this respect between summer and winter. Sometimes there is not merely a loss of a part of the oxygen in the respired air: the quantity of the azote, the other component part of the atmosphere, may likewise be altered; this seems to depend on the season of the year, and on the state of the animal, and particularly on the situation in which it had been placed previously to the examination. The number of respirations per minute varies in different persons, and also in the same person at different times. The mean may be stated at twenty. About one-eighth of the air in the chest is changed in each ordinary act of respiration and inspiration, and on an average 6661⁄2 cubic feet of air are breathed in twenty-four hours.

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"The general conviction of the close connexion between breathing and life is shown by the expressions "breath of life," "breathing one's last,' expiring," and the like. The absolute necessity for the constant performance of the changes effected by respiration, is fully demonstrated by experiments on animals which perform the function in water, as well as on those which breathe air. Thus fish die in limited quantities of water, if contact with air be prevented, and the effect will be more striking if the air contained in water have been expelled by boiling.

"We need not, then, be surprised at the serious and not unfrequently fatal consequences of those circumstances which interfere with respiration. I shall notice these under different heads."

The second lecture comprises the digestive functions, and treats of the various aliments used for food by man. The different processes of cooking, the relative nutrition of different animal food, and its comparison with that of a vegetable kind of diet, and temperance in eating : of the latter, he says:—

"The term temperance is so constantly applied to just moderation with respect to articles of drink, that it is perhaps seldom thought of as being applicable, with equal propriety, to moderation in regard to solid food. I shall, however, before I quit the subject of solid food, devote a few moments to the consideration of temperance in eating.

"The temperance in eating, which I am about to recommend, is something more than merely refraining from that degree of excessive eating, which, when given way to, to satisfy sensual appetite, is called "gluttony," and is universally despised; or that unhealthy voracity which depends on disease, and is called "bulimea," or wolf's hunger, an instance of which I have seen in a woman, who had reduced herself to absolute indigence, in endeavouring to satisfy the cravings of her appetite, although she was willing to confine herself almost entirely to bread of coarse quality.

"Many persons, I may almost say the majority of them, without falling into either of the states which I have mentioned, are in the habit of eating more than is requisite, or even good for their health. By going beyond the proper quantity of food, the system becomes oppressed by the quantity of its juices; the blood and other fluids become impure, receiving that which they ought not, and not separating from it that which should be thrown off from the system. The necessary portion of healthy bodily exercise cannot be taken without inconvenience, and the faculties of the mind are for a longer or shorter time torpid and obscured; diseases of various kinds, according to the particular liablities of the individual, are promoted; and when brought into activity are not so easily encountered or cured as when they effect the persons of the temperate. Our own great poet, Milton, was fully aware of the fatal tendency of intemperance, and after describing the angel Michael, pointing out to our first parent various deaths occasioned by accidental causes, he makes him say, that there are,

"In the Bible, there are numerous passages inculcating temperance in eating, and exposing the vice and folly of departing from it. Heathen writers have given precepts to the same tendency. Plutarch has laid down the following short and full instruction, for the preservation of health:- Keep your head cool, and your feet warm. Instead of employing medicine for every indisposition, rather fast a day; and whilst you attend to the body never neglect the mind.'

"Plutarch was an epicurean, in the true sense of the word. You will not unfrequently hear the term epicure applied to those who are devoted to the pleasures of the table; but an epicurean originally meant, one who belonged to that sect of philosophers who placed the chief good in pleasure, and the avoidance of pain: but then the pleasure which they sanctioned was generally of a pure and exalted character. Nevertheless, the epicurcans, in consulting

the ease and comfort of the body, formed a contrast with two other sects of philosophers, the stoics and the synics, who pushed temperance to abstinence and privation; and by precept and example, inculcated self-denial and austerity, and considered it a part of virtue to bear with patience and equanimity all the difficulties and misfortunes of life. It is needless for me to enumerate all those who in ancient and modern times have enforced temperance in eating; yet there is one remarkable medical authority not to be passed unnoticed. Although the individual to whom I allude is not now living, his name and his character are still fresh in our remembrance. The striking success of John Abernethy's extensive practice, essentially depended on the great stress which he laid on temperance in eating. He not only severely enforced this in his consultations, but it forms the sum of what is contained in that notorious page to which every patient was referred. Not satisfied with recommending moderation in general terms, he sometimes made his patients eat and drink by weight and measure, and thereby successfully limited them to a low, though not to a poor diet."

On intemperance in drinking, Dr. Hodgkin is still more copious and animated. As an introduction to this subject, he very properly describes the phenomena which attend the passage of fluids through the body, and the diseases which are liable to affect the vessels which contain them. The baneful effects of fermented liquors, if taken in too large quantities, and the ruinous effects of spirits on the animal economy, are practically proved :

"The use of drink is of a twofold character. In the first place, it is required to replace the loss sustained both by the vapour continually exhaling from the surface of the body and from the lungs, and by the secretions of the kidneys and bowels. Secondly, drink is required, because some of the solids taken into the stomach demand a certain quantity of fluid to reduce them to a proper consistence, and render the nutritious parts in a fit state to be taken up by the absorbent vessels. The absorption of fluids sometimes takes place so rapidly, that it has been supposed that an immediate communication existed between the stomach and kidneys; this, however, is not really the case.

"In speaking of the digestion of solid food, I had occasion to notice the absorption of nutritious matter from the small intestines, by the absorbent vessels, or lacteals, which proceed from this part of the alimentary canal towards the lower part of the thoracic duct, which canal empties itself into the veins near the heart.

"The fluids taken into the system, in part, follow the same course; although it is probable that they are not merely taken up as part of the chyle. The absorbent vessels of the stomach probably remove a considerable quantity very soon after it is swallowed, and thereby counteract too great dilution of the food. The veins, also, both of the stomach and intestines, although it has been denied by some that they perform the office of absorbents, are now believed, on the authority of the most accurate experimenters, to take up a considerable quantity of the fluid contents of the alimentary canal. The portion of drinks which enter the system through the medium of the veins, is, like that which passes through the thoracic duct, poured into the general mass of venous blood before it reaches the heart; but whereas the portion taken up by the lacteals has to pass through the glandular bodies situated in the mesentery, or web, that which goes through the veins has to pass through the liver, the largest gland in the body, which, as you know, performs the important office of producing the bile. You may readily conceive, from this fact, that errors in drink are extremely liable to disturb the liver, and bring on or aggravate those serious disorders which have their seat in that part. I

have stated that fluids find their way into the blood by both channels, before it reaches the heart; errors in drink may therefore disturb this organ; but, before the blood is sent from the heart over the body at large, it is sent from the right side of the heart to the lungs: here, as I explained to you in the last Lecture, the blood undergoes important purification, by the act of breathing; but the lungs, in the mean time, may be more or less offended by the articles conveyed to them by the blood; the very odour of some of these articles may, at times, be perceived in the breath; as, for example, when turpentine has been taken. It is not every thing offensive which enters the blood, which can be thrown off from it in the lungs; some of these articles, therefore, return with the blood to the left side of the heart; and, as the blood is sent from this side of the heart over the whole body, a portion of them must be sent to the brain; and they can scarcely fail to produce more or less injurious consequence to that most delicate and important organ. This, however, is not the only mode by which the brain is disturbed by what is taken into the stomach; there is a much more direct connexion between these two organs, by means of nervous communication, of which I shall have hereafter to speak. The baneful influence of error in drink, reaching the brain by both of these ways, is strikingly exhibited in the production of intoxication.

"Another important portion of the blood, sent from the left side of the heart, is conveyed to the kidneys; two well known glands, situated in the loins, a little below the midriff, or diaphragm. These organs perform a most important office, in separating from the blood various matters from which respiration cannot free it, but which, if retained, would be extremely injurious to the system. The most important of these excrementitious matters are, urea, the acid of urine, and some salts. You will now expect that I should say a few words respecting the kidneys. With the general appearance of these bodies you are doubtless acquainted. Although they are more or less complicated in different animals, there is a striking similarity of texture in most of them: thus, you will find the exterior tolerably smooth, and of a darkish colour, somewhat like that of liver. When cut pretty accurately through the middle, so as to separate the back, or posterior, from the fore part, you will find that the substance, to a considerable depth, resembles what is seen upon the surface; but that nearer the middle, the substance is lighter, and appears to be made up of straightish lines, spreading from one or more points which are directed towards the notch or hollow, which is always to be found on one side of the kidney. It is the outer part of the kidney in which the urine is supposed to be separated from the blood; and the lighter middle part, showing lines spreading like a fan, appears to be composed of very minute tubes, for the purpose of conveying it away. There is a funnel-shaped membranous bag attached to the hollow, or notch, at the inner side of the kidney, which receives the urine as it comes away from the points at which the tubes before mentioned meet. This funnel-shaped bag contracts so as to form a pipe, or vessel, which conveys the urine to the bladder; and it enters the side of the bladder in such a slanting, or oblique manner, that it is extremely difficult for the urine to find its way back from the bladder towards the kidney. In consequence of errors in diet, and more especially in drinks, the kidneys, and parts connected with them, may be very seriously deranged by the fluids that pass through them. It will be sufficient for me to mention two or three of these diseases, by way of example. Sometimes the kidneys are brought into a state in which they allow very large quantities of urine, sometimes amounting to several gallons, to run off in the course of the day. The urine is not only more copious, but contains principles which either ought not to exist in it, or ought not to be so rapidly separated from the blood. The urine, in these cases, is often quite sweet; it ferments, like beer, and frequently attracts flies. This disease is called diabetes, and is almost invariably fatal.

"Another affection of the kidneys consists in the external, or secreting part, being deranged by a deposit of whitish colour; which gives the kidney a mottled appearance, and often renders its surface uneven. Kidneys, in this state, often produce a considerable quantity of urine, which is sometimes pale, and sometimes of a dingy, or smoky colour; its healthy properties are considerably altered; and it contains nutritious matter which ought not to escape by the kidney. This form of disease is quite as fatal as diabetes. Persons affected with it are very liable to various kinds of dropsy, to apoplexy, and disease of the heart. When they meet with accidents, the injured parts have very little disposition to heal; and when they become the subjects of other diseases, they have very little power to resist their fatal tendency. I believe that many hundreds of individuals have fallen victims to this state of the kidneys, without this cause having been even suspected. It often occurs where it cannot be ascribed, at least solely, to intemperance in drinking. The abuse of mercury, or exposure to cold, seems often to have co-operated with intemperance, or may have been the only discoverable exciting cause.

"The last affection to which I shall here call your attention, belongs to the urinary passages, and depends upon the urine itself. When, from various causes (of which errors in diet, and more especially in drinking, appear to be by far the most frequent), the urine is charged with a larger quantity of saline and other matters than it is capable of dissolving, a portion of these is necessarily separated in a solid form; and by their cohesion, either in small grains, in grains of a larger size, or in absolute masses, they constitute urinary sand, gravel, or stone, the painful and serious effects of which are too generally known to require any description here from me."

The pernicious qualities and bad effects of tobacco and snuff, of chewing and smoking, are pointed out in a clear and pointed manner; of the latter, it is remarked :—

"It might be supposed, that as tobacco is necessarily burnt when employed in SMOKING, its injurious properties are destroyed. This is by no means the case. The active principle of tobacco consists in an oil, called an essential or volatile oil, because it can be raised in the form of vapour, like water or spirit. This oil, when separately collected, is one of the most active poisons known. In smoking, a small quantity of it is drawn into the mouth, where it mixes with the saliva. Its poisonous effects are more conspicuous in inexperienced and young smokers, not only because their nerves are unaccustomed to it, and therefore more sensible to the effects of a small dose, but because they are more apt to swallow the spittle contaminated with the smoke: and also, by quickly drawing the air through the burning tobacco, they cause a larger quantity of oil to reach the mouth. The poisonous effect of tobacco, as exhibited on raw smokers, are giddiness, intoxication, and distressing sickness, which continue for a considerable time. Notwithstanding these effects, a silly and childish notion, that smoking is a very fine thing, and makes those seem manly, who have little or nothing of manliness to recommend them, induces the young smoker to go on until his sensibility is blunted to the unpleasant effects, and he is only conscious of the seducing excitement or stupidity which he finds so delightful, that the temptation can hardly be overcome."

The third lecture, treats of the muscular motions and the intellectual faculties, and is altogether a highly interesting lecture. It includes the effect of exercise upon the circulation, and the influence of particular trades. Speaking of the tendency of brutalizing sports to perpetuate the barbarous forocity of the people, the author is naturally led to the subject of war, upon which a series of remarks are offered in the highest degree philosophic and Christian. Of the former, he says: