CHAPTER VI
THE BEATING OF THE HEART
I
In all ages and by all peoples the heart has been looked upon as the centre of the passions, of feeling and of strength. Our word courage comes from 'cœur’—heart. Nearly two thousand years ago it was proved by physiologists that the heart was not the centre of sensibility, and yet poets and common opinion continue to say that the heart is the most sensitive part of the body.
In August 1879 Biffi showed in the Instituto Lombardo the heart of a youth, in the left wall of which, in the autopsy, he had found a needle sticking. The youth, who was of good family, was a poor unfortunate who had killed his father in a fit of insanity, had then tried repeatedly to commit suicide, and at length died mad in the hospital. While he was still living with his family, about two years before his death, he had said that he had stuck a needle into his heart, in order to put an end to his life, but no one believed him. During the whole time which he spent in the hospital the movements of the heart were regular and quiet, the pulse normal, respiration easy, sleep good; he could lie in all positions, and he never complained of any oppression in the region of the heart. When he was dead a needle with a rusted eye was found buried in the flesh and covered with a sheath which had grown around it; the sharp, polished point had penetrated into the cavity of the heart. The irritation caused by the perpetual pricking had produced fleshy excrescences at that point where the heart was continually grazed.
This instance shows how insensible the heart is, and yet, in the language of the poets and in the imagination of the people, it will always remain the centre of the passions and of feeling, because during fear, and in the decisive moments of life, we feel it hammering against the walls of the chest like a machine hidden within, the force of its contractions booming and echoing in our ears and head, exciting that strange feeling of oppression which we imagine that this rebellious organ, unchained by a storm of passion, alone produces.
The heart is nothing but a force-pump situated in the centre of the blood-vessels, which, by the play of its valves and the contractions of its muscles, keeps up the circulation in arteries and veins, driving the blood into all parts of the body, an arrangement without which life would be impossible.
II
In studying a machine one first seeks the most important part, without which it could not move nor work. In the mechanism of our body, the first part to develop and move is the heart, and it likewise is the last to stand still. The development of this organ may be better studied in the hen’s egg than in any other animal, as it can be seen on the second day of incubation. At its first appearance it is in man, as in animals, a fine, curved tube in the shape of an S. If we break an egg taken from under a brood-hen towards the end of the second or the beginning of the third day, the first rudiment of the heart may already be seen pulsating. Towards the end of the fourth week after conception, the human heart has already nearly the form which it preserves during the whole of life. It is wonderful with what resistance the heart struggles on its first appearance against every cause which threatens its life. Professor Pflüger relates that a human embryo of about three weeks’ gestation was left a whole night between two watch-glasses in a cold room. In the morning it was found that the little heart still contracted at intervals of twenty to thirty seconds, and these movements were noticeable for almost another hour, becoming gradually slower and weaker until the complete death of the embryo.