I suppose you have been either near or inside a factory. You have heard the noise of the shafts and the pulleys and machinery. You have seen the carding machines, and listened to the noise of the great spinning jacks which twisted the cotton and the wool into yarn or thread, and heard the deafening sound of a great many looms as the shuttles flew backward and forward, while the many threads were being woven into cloth. A factory is quite wonderful, but do you know that in your bodies are found the elements of almost all the kinds of machinery that are used in the world? God has so created us that we do not hear the noise of the machinery of our bodies, but if you will place your fingers gently in your ears you will hear a peculiar roaring sound. That sound which you hear is the noise of the machinery of your body, which is in constant motion.
Now, the heart, which pumps the blood into all portions of the body, makes the greater portion of this noise. Do you know where your heart is located? I supposed that most of you would point to your left side, because you have so frequently heard it spoken of as being located there. You have seen public speakers and others, when referring to their heart, place their hands upon their left side. But if you will bend your head forward so as to press your chin against your breast, as far down as possible, the heart will be under and a few inches below your chin. It is in the center of the body, and the lower portion of it comes near to the ribs on the left side, and when it beats we can feel it throb by placing our hand upon our left side; but the heart is more nearly in the center of the body, and not wholly at the side. If you were to close your hand as the boys do when they say they make a fist, the size of your closed hand will be somewhat smaller than the heart.
Water and Syringe.
In this tumbler I have some water which I have colored with red ink, so as to represent blood. Here is a small glass syringe, such as can be bought for a few cents in any drug store. Now, when I draw this little handle up, you will see how the syringe is filled with this red water, and when I press it down how the water is forced out of the syringe back into the glass. This very clearly illustrates the principle upon which all pumps and steam engines which pump water are made. Even the large fire engine, which throws water such a great distance, is made largely upon this principle.
You may possibly have been in the engine room, where the huge pumps force the water into the reservoirs which supply the city with water for drinking and other purposes. From the pumps and the reservoirs there are great pipes which lead the water under the streets to many thousands of houses which compose the city. After the water has been used it is turned into the sewers, runs down into the river and back to the sea, where it is evaporated, rises again in the clouds, and by the wind is carried hundreds of miles over the country. Then it descends again in the form of snow and rain, soaks down through the earth and finds its way again into the springs and great veins of water under the earth, from which it is carried back once more to the city. Thus it is made pure again and again, to be used over and over by the people whom God has created and whom He supplies with water in this way.
Now, in somewhat the same way, the heart, which is both an engine and a pump, forces the blood out through the pipes or tubes of our bodies called the arteries, distributing it to every portion of the body, furnishing the materials for building and renewing the muscles and the bones and every portion of our system. Then gathering up that which is worn out and no longer of service, the impure blood returns through the veins back to the right side of the heart, where it is pumped into the lungs and purified by being brought into contact with the air we breathe. The blood is then returned to the left side of the heart, pumped again into the arteries and distributed through all parts of the body, and so it goes on circulating. Thus the blood is pumped by the heart into the arteries and is distributed to all portions of the body, and returned again to the heart, from fourteen to twenty times each hour of our life.
In this bottle, which holds six ounces, I have placed some of this colored water, which represents about the quantity which is pumped out of the heart of an adult each time the pulse beats. As I have already intimated to you, the heart is double, and at each throb about one-half the quantity in this bottle is pumped out by the right side, and the other half by the left side of the heart. Now, if the heart were to pump different blood with each pulsation, instead of pumping the same blood over and over again, in twenty-four hours the heart of a man of ordinary size would pump 150 barrels of blood.
A Wagon Load of Barrels.