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Beating of the Pulse Explained.
129 pushed, soon divides, somewhat as the trunk of a tree does.First a branch
goes off here, then another here; then two or three almost at once; and these branches subdivide, too, till, they are so small that they can hardly be seen by the na
But small as they are, the blood goes from the heart into them all; and in all the larger ones there is a beating perceived, the same as at the heart; and this is what physicians mean when they speak of the pulse. It is a jerk of some branch of the great artery I have spoken of. The physician almost always
feels of the branch of the artery which goes along in the wrist, because it comes so near the outside there, that he can find it; whereas most of them go so deep in the flesh that the finger cannot readily feel them.
If any one should express surprise that a jerk should be perceived so far from the heart, I may refer him to the following illustration.
Suppose a long hollow trough or pipe, all the way of a size, were filled with little blocks eight inches long, lying close to each other. Suppose there were a hundred or more of them, and suppose you should push at one end of the row; would they not all be moved alike? And if you should strike one end of the row with a hamıner or sledge, so as to produce a shock, would it not be felt quite to the other end of the row in the same instant? Would it not be so, even if the row was a mile long? Just so with what I might call a row or column of liquid substance, as the blood. The heart pushes with a jerk at one end of the column, and the motion and jerk are felt quite to the other extremity, in the very same instant. I might also illustrate the subject in another way,
if seen a fire engine, and seen it in operation. The long leather pipes, through which they force their water, might be compared to the great artery of the human body; and the engine itself to the heart. Now, if the pipe or hose that carries the water, is two hundred feet long, it takes a very strong man to hold the end of it, so as to point it exactly right, towards the fire. It jerks with violence, even at the very end of it.
The arteries,—that is, the branches of the great artery--are whitish, especially the large ones. Those are not arteries which you see on the surface of the body and limbs, especially of old people ; and which look bluish. They are veins. The white pipes or arteries, as I have already told you, lie deeper; and can only be felt at particular places, where, to get around some bone or joint, they come very near the surface.
The veins, indeed, carry the blood in thein ; but it is that blood which after having been sent out in the arteries to all parts of
Plan for Purifying the Blood.
the body is going back again to the heart, from whence it came. For it is time for you to know that these two processes are going on in us every moment, as long as we live. The heart sends out blood through the arteries, at every contraction; and it goes to the most remote parts of the body. Then having done its work in every part, it runs back again through the veins, and is emptied into the heart. It goes out from the hollow in the left side of the heart, and returns into the hollow on the right side. So that you now begin to see how the heart is constantly supplied with blood to send out ; that is to say, how, after it has pressed its contents into the great artery, it gets filled again.
But the two hollow cavities in the heart have nothing to do with each other, in a healthy person, any more than if they were two separate hearts. There is no door, nor any sort of direct communication at all between them. How then, you will ask, does the blood that comes back through veins, into the right apartment, get into the left to be sent out again ? The question is a fair one, and shall be fully answered.
The blood sent out of the heart, from the left apartment or ventricle, to all parts of the body, through the great artery, is of a bright red, and quite pure ; but as it proceeds it becomes impure, in various ways; and when it has got out of the little arteries in the extreme parts of the body into the litile veins which lie all around them, it becomes of a dark red; and becomes more and more impure; and the inpurity and darkness of color continually increase, till it gets quite back into the right apartment or ventricle of the heart. By this time, it is altogether unfit to be circulated any more in the body. So it is pressed out of the right ventricle of the heart, to which it had arrived through some shorter arteries, into the lungs, or lights, as they are sometimes called, where, by a process which I cannot stop here to describe, the blood is completely purified. As soon as this purifying or cleansing process is completed, it is carried back by short pipes or veins, to the left ventricle of the heart ; where it is immediately sent out to all parts of the body, as I have already
I will repeat, briefly, the process ; for I wish you to understand it perfectly, before we go any further. The heart contracts with a jerk, and presses the blood of the left ventricle (or cavity) into the great artery, which by its thousand and ten thousand branches, continually distributes it to all parts of the body, even to the extremest ends of the fingers and toes; the small veins then take it up, and, like so many thousands of little streams, run into larger and larger ones, as they proceed towards the heart, into whose right ventricle they at last empty
Wonders of the Circulation.
themselves; and no sooner is this ventricle full of this dark colored, impure blood, than it immediately contracts and squeezes its contents into an artery which carries it to the lungs, where it is purified, and then sent back to the heart in another set of vessels or veins, to be conveyed out again, in its new and healthy condition, to all parts of the system.—One thing, however, it is desirable you should understand. At the instant when the heart contracts on one side to send out blood to all parts of the body, it also contracts on the other side, to send it to the lungs to be purified. This makes the process more simple than at first view it would otherwise seem to be.
This then is, in few words, the course of the circulation of the blood, in the human body. The whole mass of blood, in a middling sized adult, is estimated at from twentyfive to thirty pounds; or a quantity somewhat exceeding a common sized pail full; and a quantity equal to all this, goes through the heart, as well as through the lungs, once in from three to four minutes. The circulation has sometimes been regarded as double, or formed of two circles united at the heart or centre, as are the two circles which form the figure 8. In this view, the lower half of the figure represents the path of the blood, as it passes from the heart round through the arteries and veins, and back again to the heart; and the upper half of it, the course it takes from the heart to the lungs to be purified, and back again to the heart or centre.
The use of the circulation--that is to say, the purposes which are subserved to the living system by having a pail full of blood pass over the whole body fifteen or twenty times an hour, or from three hundred and sixty to four hundred and eighty times in a day—I have not now time to show. All I can do at the present time, is to remind you of the goodness as well as wonder-working power of God, in keeping up such a course of incessant action. Think of a pail full of blood rushing through a small human heart, every three or four minutes, day after day, and year after year! Think, too, of the heart's incessant and curious labor! Why, its contractions or beats, at only sixty a minute, amount to 3600 an hour ; 86,400 a day; and 31,536,000 a year. In a life, supposing it to be protracted to 80 years, and the beats to average only 60 a minute in every part of it, the amount would be no less than 2,522,880,000.
Pres. Lindsley on Common Schools.
INFLUENCE OF COLLEGES ON COMMON SCHOOLS.
We spoke, not long since, of a speech in behalf of the University of Nashville, by Pres. Lindsley; and promised a further notice of it. The following is a brief extract, showing his views of the influence of colleges and universities on common schools and common school education. So highly do we regard his sentiments in general, on education and instruction, and so generally do they accord with our own, that, though we have hitherto thought less favorably than he, of the influence of colleges, we are quite willing to hear his opinions, even on this point.
• The university,' says he, 'has ever been the friend and the nursery of common schools, when left to its own natural freedom of action. In modern times, wherever the university has flourished, untrammelled and unrestricted by jealous, arbitrary authority, there the common school has taken root and prospered also.
• This fact is notorious, indisputable and undisputed. In no country, at this day, do we behold the slightest approach to a good common school system, except where the university is honored and liberally sustained. Scotland, Prussia, Germany, Holland, New England and New York may serve as proof and comment. I hold the attempt to create and foster common schools, without the aid of the university, to be utterly vain and nuga
It cannot be done. But establish an efficient, freeworking university any where—whether among the Turks, the Tartars or the Hottentots—and the common school will spontaneously grow up around it and beneath its influence, as certainly as light and heat flow from the sun in the firmament. It is in fact the great luminary of the intellectual firmament.
• The common school is the child and not the parent-the effect and not the cause-of the university. The university will furnish the teachers and the learning which are indispensable to the inferior schools and seipinaries : and it wil awaken the desire and the ambition among all classes to acquire knowledge and to support schools.
• No man can teach what he does not thoroughly understand. Whatever art or science he professes to teach others, he must first learn himself. If you would have competent teachers of reading, writing, arithmetic, grammar, history, geography, the constitution and laws of the land, and whatever else our youth ought to learn at school in order to become useful citizens, you
How to obtain American Teachers.
must first provide for their proper training. That is, you must send them to the higher schools and colleges and universities of your own or some other State.
' A thousand young men ought now to be thus in training, or in a course of preparation for the business of schoolkeeping, (for Tennessee.] Send them to the University, at the State's expense, and they will not fail to become qualified for the service in due time. Or, enable the University, by suitable endowments, to open her doors to all comers, and to educate every poor talented youth without charge; and you will soon be supplied with indigent but accomplished scholars, who will be glad to teach for a livelihood. They will themselves become pioneers and missionaries in the cause of education. They will search out and expose the wants and destitution of the people, and will plant schools in every village, and in every neighborhood, where children can be found.
Tennessee, with her present ample resources, might organize and endow a University which could impart gratuitous instruction to all her studious and deserving youth; and thus eventually elevate the standard of education, and insure its adtages to every portion and order of its rapidly increasing population.
· Having on various occasions heretofore, discoursed at large on the subject of common schools—having reviewed the systems which obtain in all our States and in several countries in Europe—having expressed my opinions freely upon each, and also upon the expediency of providing schools for the education of teachers, &c., it was not my purpose, in the above remarks, to do more than barely to point out the dependence of common schools upon the University. Our poor college graduates will, after all, prove our best common school-masters, even though they may not be ambitious to teach for life. Well educated and clever Americans will not be content to work like Prussians, in comparative obscurity and poverty. The planter's overscer or negro-driver is better paid for his learned labors, than any common school teacher in all the valley of the Mississippi.