tressing malady commonly known as hydrocephalus, or water in the brain. A cure for this, in children, has lately been discovered, by perforating, or making a hole in the top of the skull, and drawing off the water by a syringe. The brain is said to be larger in man, in proportion to the nerves belonging to it, than in any other animal. It is conjectured by some to be the grand and primary organ of sense, with which the mind is supposed to be most immediately and intimately connected, and from which the Nervous Influence is found to be communicated to all the other parts of the body. By others, however, it is maintained, that the immaterial, immortal spirit in man, does not reside exclusively in any one part; but lives in all parts of the brain, spinal marrow, and nervous system in general.*

As a proof of the connection of the brain with the other parts of the body,-with the stomach, for example,—if a person receive a violent blow on the head, he becomes sick; or if the stomach be disordered, head-ache is frequently the consequence. Take another instance. A man once came to Sir Astley Cooper, complaining of a dreadful pain in his back, which made him stoop, so that he could not lift himself up. Sir Astley examined his back, but could find nothing the matter there. The man said he had lately been fighting, and had had several heavy falls. The surgeon then examined his head, and there found a small bit of his skull broken in, and resting on the brain. With an instrument, Sir Astley lifted up the piece of skull; the man at once rose up, and felt perfectly relieved. Thus the seat of pain was in the back; the source of it in the head.

The brain being so important, and tender, and delicate a portion of the human frame, is providentially protected by an arch of the firmest construction, viz., the skull.

2. The SPINAL MARROW is a continuation of the substance of the brain, passing, like a white cord, down the vertebræ, or back-bone. From this are given out thirty pairs of nerves,

* Phrenologists assert that the brain consists of thirty-five organs or faculties. These they divide into two kinds, viz., feelings and intellects; and these are again divided and sub-divided. They, moreover, assert that the protuberances in the skull correspond to the size of the particular organ in the brain within; a small faculty being an indication of small power, and a large one vice versa. Now that there is truth in Phrenology, so far as regards the position and size of the brain, we think is evident; but of the particular mapping of the skull, as adopted by Phrenologists, we may be allowed at present to remain in modest doubt.

which, in conjunction with those arising from the brain, communicate energy and feeling to the whole body; and also by their extreme sensibility, convey to the brain the slightest as well as the strongest impressions made upon the different organs; hence our pleasures and our pains, our hopes, our fears, and our affections. The least injury done to the spinal cord, even so much as the prick of a pin, causes death. By striking at the spinal marrow, at the back of the head, the animal, under the butcher's hand, is at once brought low, and lies dead at his feet. At the gallows, when the body falls, the neck is dislocated, the spinal cord is broken, and instant death is the result.

We see, however, what care the Creator has taken of the spinal cord, in causing it to pass down the centre of some of the strongest bones of the body. Solomon, no doubt, refers to this in his expression-" Or ever the silver cord be loosened."

form something like a pear. Its size varies in different persons; it is not much larger than a man's fist, being nearly the size of the heart of the calf. It is generally about six inches long; and, at the upper part, four or five inches wide. It is situated in a slanting position on the left side of the body, just under the upper or true ribs; and is embedded, as it were, in the left lung. (See fig. H.) It is surrounded by a membrane or pouch called the pericardium, (a word which means round the heart.) This membrane secretes and contains about a spoonful or two of limpid fluid, resembling water, which prevents the surface of the heart from becoming dry by its continual motion. It was this which was pierced by the soldier in the body of the Redeemer, when he hung upon the Cross, and from which the water flowed mingling with, or followed by, the blood. John xix. 34.

The weight of the heart is usually from ten to fifteen ounces. It is the centre of the circulation of the blood; acting like a force-pump for sending the blood through the various arteries or channels of the body; and may be likened to the waterworks which send water through a town in pipes. How minute and multiplied the ramifications of the blood vessels are; and how thickly spread over the body, is proved by the fact, that we cannot prick the point of a pin into the flesh, without drawing blood; that is, without finding a blood-vessel. The heart is a double organ; one half presiding over the circulation in the lungs, and the other over the circulation in the rest of the system, or the body at large. The right side of the heart, which is the smaller, is divided into two cavities or chambers, called auricles and ventricles. The left side of the heart is also divided into two cavities; but these are larger and more strongly constructed than those on the right side; having to conduct the circulation through all parts of the body, except the lungs. By the contraction of the ventricles, the blood is sent into vessels, called

2. ARTERIES, and carried by them to every part of the frame, for the purposes of nourishment, preservation of life, the production of warmth, and the secretion or absorption of different fluids. There are, strictly speaking, but two arteries; the PULMONARY artery, which proceeds from the right ventricle of the heart; and the AORTA, which proceeds from the left ventricle. All the others are only ramifications or branches of these; they are, however, all denominated arteries; and each has its appro

priate name. The motion of the blood in the arteries is called the pulse, which corresponds with the beating of the heart. The pulse may be felt in various parts of the body; but the most usual place of feeling it, as most convenient, is at the wrist. From seventy to eighty strokes of the pulse in a minute, are commonly that number which, in an adult person, is considered, as far as the pulse is concerned, to indicate health. In children, however, the pulse is much quicker, and in old persons slower. The number of contractions or beatings of the heart, which, of course, occasion these pulsations, is rather greater in the standing position than in the sitting posture; and in sitting, than in lying down. It is increased by exercise, especially by ascending a steep hill, or going up stairs; and also by any mental excitement.

Wounds in arteries are always dangerous, and very frequently mortal; hence the wisdom evinced in the structure of man. All the arteries are deeply embedded in flesh, or other surrounding substance; while the veins, a wound in which is comparatively unimportant, are plentifully scattered on the surface of the body. When the blood has been sent up, from the left side of the heart, by means of the great artery called the AORTA, it spreads in innumerable vessels over the whole body; but when they arrive at the extremities, at the end of the fingers and toes, for instance, the blood is taken up, or re-collected by another system of vessels, termed

3. VEINS, which are also spread over the whole body, and bring the blood back to the right auricle of the heart. There is no pulse in the veins. The blood flows through them very slowly. In going out of the heart, it passes from wider into narrower tubes; and in coming back, from narrower into wider. The blood having now passed through every portion of the body, comes back to the heart in a dark, red, impure state. It is then propelled by the contraction of the heart into the large artery, called the PULMONARY artery; leading directly, by separate branches, to the two lungs; where it is purified by the air, which is drawn into them, and then passes into the left ventricle, the point from which it started; and now, being oxydized or cleansed, is of a bright red colour, and is distributed anew over the frame. "Thus there are two distinct circulations, each carried on by its own system of vessels: the one, from the left side of the heart to every part of the body, and back to the right side; and the other, from the right side of

the heart through the lungs, and back to the left. The former has for its object nutrition and the maintenance of life; and the latter the restoration of the deteriorated or impure blood."*

As the pure air which we inhale, or draw in, purifies the blood, it is of importance that we do not breathe the same air again and again, which we may do in a small, confined, crowded room. If the air we breathe is not pure, it does not sufficiently change the blood from its black to its scarlet colour. "It is consequently sent back to the heart, and distributed all over the body, in a state totally unfit for the purposes for which the great Creator designed and gave it; and if this abuse is long permitted, the health materially suffers. Instances have been too frequently before us in the crowded state of lodging-houses, rooms in which large families reside, workhouses, prisons, &c., and one particularly in the celebrated Black Hole at Calcutta, to need our saying more on this subject." How careful ought you to be that the rooms in which you sit, and particularly those in which you sleep, are not too tightly closed, or too long shut in! And how easy is it to raise a window, or to open a door! And though you might thereby be exposed to cold, (avoid, however, a draught,) yet how much more injurious on the whole, must it be to sit in close apartments, and continually to breathe a contaminated atmosphere! Remember, then, that air, which has been once breathed, may be considered as unfit for further respiration, and as totally spoiled for the purposes of animal life. The air is nowhere so wholesome as out of doors; and there, accordingly, every human being should spend, if possible, some portion of every day.

The entire quantity of blood in a full-grown person is estimated to be from twenty-four to thirty pounds.

The circulation of the blood was known, though imperfectly, by Plato, whose description is rather curious. "The heart," says he, "is the centre or knot of the blood-vessels; the spring or fountain of the blood, which is carried impetuously round. The blood is the pabulum or food of the flesh; and, for the purpose of nourishment, the body is laid out into canals, like those which are drawn through gardens, that the blood may be conveyed, as from a fountain, to every part of the pervious body." It is, however, to Dr. Harvey, an eminent physician, who lived under the reign of James I., that the world is indebted for a complete and accurate discovery of the circulation

*Combe's "Principles", &c., p. 211.