NOVEL FACTS ABOUT TEARS

Golden Bay Argus, Volume XII, Issue 47, 21 April 1910, Page 3

NOVEL FACTS ABOUT TEARS

The latest medical studies have proved clearly, on the authority of Dr. Romme, that tears serve a very useful purpose in protecting our eyes. This great French physician now presents some further facts which are of great interest. He says it is a mistake to suppose that tears are merely a sign of weakness and foolishness, to be displayed only by women and children. They are a valuable safety vent to protect jus from the effects of certain violent disturbances of the circulation, which might cause apoplexy, madness, or even death. The value of tears can only be understood after a study of the arterial system of the head and neck. On each side of the neck there is an artery, known as the common carotid artery. Near the larnyx (the organ of voice,) it divides into two branches, one of which, known as the internal carotid, carries blood to the brain, while the other, the external carotid, carries blood to the face and scalp. These two great channels of circulation are not entirely independent of one another. Not only have they a common origin, but they communicate again in the neighbourhood of the eyes through the ophthalmic artery. This arrangements of the arteries explains why the blood pressure may become dangerous in the vicinity of the brain, and may be relieved by tears. If we look at a' person of fleshy build and sensual character, who is laughing very heartily, we shall find that tears arc rolling down his or her cheeks. When a person is going - to laugh very heartily he begins by contracting the muscles which close the throat. He lowers his diaphragm'(the inside partition between the upper and lower part of the body), and makes rigid the muscles of the upper body. As the laugh proceeds he calls into play other muscles. "During a violent laugh," says the great Darwin, "the entire body is thrown back and shaken ; the subject almost falls into convulsions ; the respiration stops."

The brain congestion by which the laughing person is threatened is aggravated by the contraction of the muscles of the face, which gives to anyone the peculiar expression associated with laughter. Without relief something would burst in the brain. But by the ophthalmic artery the extra blood which has started towards the brain flows away in the direction of the eyes. In 'doing so the blood causes a pressure on the tear glands, which immediately show the fact by a flow of tears, which is more or less abundant, according to the violence of the person's laughter and the development of his glands. Investigation by the microscope has shown that a tear is composed of water and .fatty matters and salts in solution with some crystallisablo substances of organic origin. The albuminous , (containing nitrogen) matters are albumen; paraglobuline (a substance in the blood from which solid fibrin is formed) and fibrinogen (fibrin in its fluid state in the blood). The salts are principally sodium and potassium chlorides, phosphates and sulphates, together with lime and magnesium ahosphates. The tear glands constantly secrete a moderate quantity of tears, which are necessary to keep'the ejeballs damp and healthy. This normal tear supply runs away through the nasal duct, into the nose. When grief is violent this duct is insufficient to carry away the tears and they overflow and run down the cheeks.

The- tears that flow in grief or vexation are caused by a movement of the blood in another direction, but they are equally valuable in protecting health and life. It is often said that a person's grief is too deep for tears. This is an old saying, and medial science now shows that it contains a good deal of sense. The truth is that the grief which is tearless is much more intense, and leaves a much more painful impression on the sufferer.

The physical mechanism of tears remains to be explained. The grimaces which we make when we weep are caused by the contraction of muscles which act upon the tear ducts and the ophthalmic artery. The tears then flow, relieving the blood pressure. This anatomical arrangement seems planned! to facilitate the secretion and flow of tears in cases where it is useful or necessary. 'Among little children whose nervous system is so delicate tears constitute a most important safety valve, which insures the safety of their brains. The rivers of tears which flow from their eyes at the least provocation are the best remedy against the nervons shocks that life does not spare them. Here is a curious fact to note that babies up to the age of one year do not weep. The loud howls and complaints which they utter so frequently at this early period are not accompanied by large, wet tears. They have not reached an age when they can experience real mental troubles and griefs, and therefore they have no occasion for, tears. The active development of the tear dtucts is coincident with the development of conscious intelligence in children. It is quite certain that women cry more frequently than men. The woman has a much more delicate and impressionable nervous system than the man. The blood rushes more rapidly towards or away from her brain with the varying emotions of joy and sorrow. The effect of this blood pressure would be particularly dangerous if it Were not for the fact that woman has a large and atun-' dant supply of tears at her command. '-'. '": f

The woman's physique is soft and fleshy, instead of being hard, muscular and compressed, like that of a man. There is more liquid in her tissues, and this insures -a better supply of tears. Her glands are more highly, developed , than , „ ttyg man's, and this applies .particularly to the tear glands. The amount pf tears a person can shed varies enormously with different individuals, JS& IreKfiuenUx see a child ween tUi iAa

tear ducts are dried-up ana men sod without tears.

But a large lymphatic womatt can weep copious tears with brief intervals for a whole day and repeat the process day after day. There are many actresses who weep real tears every evening for months. They have acquired control over muscles which in ordinary only operate involuntarily. In old men, the tear ducts usually shrink to such an extent that weeping becomes practically impossible. Very old people receive the news of losses which in middle life would have convulsed them with grief with almost complete indifference.

Most of the animals have tear ducts, but they do not, according to modern history authorities, shed tears as the result of joy or grief. The latter habit is an essentially human characteristic. The tears of animals only flow in consequence of some interior disorder, or some external irritation. Their principal function is to clear the eyes from foreign objects. In the oldest literature, there are frequent references to ."crocodile tears." It pleased the early naturalists to imagine, that the crocodiles purposely shed tears in order to attract the attention of the passers-by, and that when they came to sympathise with him he seized the opportunity to swallow them up. Modern naturalists, however, hold that there is no good evidence for believing that the crocodile craftily assumes grief for the purpose of misleading travellers. It is true, however, that the crocodile has most remarkable large tear ducts, and if one watches one of these reptiles long enough one is sure to v see him sheding copious tears. The large tear ducts evidently exist for the purpose of washing, away the numerous foreign particles that collect in the eyes of the reptile as he floats on the water.—" Popular Science Siftings."