fuel. Hunger rings the bell, and orders up coals in the shape of savory meats. Or, should the summons be neglected, the garnered fat, is thrown into the grate to keep the furnace in play.

"If, on the other hand, the heat of the body should become unreasonably intense, a very cunning process of reduction is adopted. When a substance grows too hot, the simplest method of bringing it into a cooler frame is to sprinkle it with water. This is precisely what occurs in our human frames. For no sooner does our internal heat rise above its standard height, than the perspiration tubes, with their six or seven millions of openings, indignant at the event, begin to pour out their fluid, so as to bathe the surface of the whole body. Whenever, therefore, a man becomes overheated by working, running, rowing, fighting, making furious speeches, or other violent exertions, he invariably resorts to this method of quenching the heat, by pouring on water.'

"Looking at the question from a mere human point of view, could any project appear more hopeless than one for burning fuel in a soft, delicate fabric like the human body-a fabric composed for the most part of mere fluids—a fabric which might be easily scorched by excess of heat, or damaged by excess of cold? Does it not seem strange that a stove should have flesh for its walls, veins for its flues, and skin for its covering? Yet here is an apparatus which, as if by magic, produces a steady stream of heat-not trickling penuriously from its fountains, but flowing on day and night, winter and summer, without a moment's cessation, from January to December.

"Carry this splendid machine to the coldest regions of the globe, set it up where the frosts are so crushing that nature seems to be trampled dead, still it pours out its mysterious supplies with unabated profusion. It is an apparatus, too, which does its work unwatched, and, in a great measure, unaided. The very fuel, which is thrown into it in random heaps, is internally sifted and sorted, so that the true combustible elements are conveyed to their place, and applied to their duty with unerring precision.

"No hand is needed to trim its fires, to temper its glow, to remove its ashes. Smoke there is none, spark there is none, flame there is none. All is so delicately managed that the fairest skin is neither

shrivelled nor blackened by the burning within. Is this apparatus placed in circumstances which rob it too fast of its caloric? Then the appetite becomes clamorous for food, and, in satisfying its demands, the fleshy stove is silently replenished. Or, are we placed in peril from superabundant warmth? Then the tiny floodgates of perspiration are flung open, and the surface is laid under water until the fires within are reduced to their wonted level.

"Assailed on the one hand by heat, the body resists the attack, if resistance be possible, until the store of moisture is dissipated; assailed on the other by cold, it keeps the enemy at bay until the hoarded stock of fuel is expended. Thus protected, thus provisioned, let us ask whether these human hearths are not entitled to rank among the standing marvels of creation? For, is it not startling to find that, let the climate be mild or vigorous, let the wind blow from the sultry desert, or come loaded with polar sleet, let the fluctuations of temperature be as violent as they may without us, there shall still be a calm, unchanging, undying summer within

as?"

The temperance of the body is about one hundred degrees Fahrenheit. The liver is the warmest organ. The fingers and toes may suffer most from cold without seriously endangering life. If the trunk of the body is cooled down even a few degrees below one hundred Fahrenheit, death is certain to ensue.

RESPIRATION AND CIRCULATION.

Some muscular actions of the human body are worth considering here. One of the most important and beautiful is that of respiration. No person can live without breathing, nor stop breathing at will. The breath may be "held" for a few seconds, but not longer. The breathing process animates the living organism, and invigorates all its movements.

The lungs are the principal organs of respiration. Their texture is soft and spongy, giving them the property of easy expansion and contraction. When they receive the air by inhalation through the windpipe, they enlarge in every direction, causing even an expansion of the chest. At every breath they take twenty cubic inches

of air, (one-third of a pint) which makes about six hundred thousand cubic inches a day. This is about eighty times the bulk of the whole body. From this inhaled atmosphere, the blood vessels of the lungs appropriate the nutritious qualities and carry them to the heart, which in turn circulates them through the entire system. But for this enrichment of the blood at every breath by the oxygen of the air, the whole quantity of blood in the body would speedily become blue, the lips would turn purple, and the face assume a dark ashen color, just as when a person is choking. This would be followed by the complete loss of vital properties in the blood, and the living machine, deprived of its nourishment, would stop its action, decay, and die. This simple statement will serve to indicate the necessity of pure air, and plenty of it, in order to a state of perfect health.

The movements of the heart constitute another deeply interesting phase of life. The heart is a powerful and tireless little organ, constant in its action, and wholly independent of the volitions of the will. Whether we sleep or wake, walk or sit, work or play, the heart beats on, and stops only when the immortal spirit wings its flight. About one-eighth part of the human body is blood; so that in a man weighing one hundred and sixty pounds there are nearly twenty pounds of blood. After the digestion of food at each meal, this amount is considerably increased, for the blood has then absorbed the nutritious materials which the food affords, and these materials can reach the tissues of the body to impart new strength only through the circulation. After long abstinence from food the quantity of blood is correspondingly diminished. The body cannot endure the loss of much blood. Fainting follows the loss of one pound, and complete unconsciousness that of two. If three or more pounds of blood be taken away at one time, recovery is said to be impossible.

If you place one of your fingers into your ear, a roaring sound will be heard, which Dr. Hammond says is the sound of the circulation of the blood.

Try it, and think what a wonder of a machine your body is, that even the points of your fingers are such busy workshops that they roar like a small Niagara. The roaring is probably more than the