ACQUIRED DISEASES FROM MECHANICAL CONCUSSIONS AND SHOCKS.
The effect of repeated concussions upon the body is to produce a varied series of diseased conditions affecting various organs of the body. Iron plate workers, owing to the constant noise to which they are subjected, especially during the process of rivet ing, suffer much from the vibration. They are deafened by it, and in some instances are rendered permanently deaf. In other instances the circulation through the brain is disturbed, so that giddiness and nausea follow as results. These phenomena are produced in certain of the workmen much more readily than in others, and occasionally incapacitate them in the very outset of their career. Some experience a temporary annoyance which, a time, they get over, the ear becoming less sensitive to the din. In a third class of cases the first oppression is tolerated, and the ear becomes accustomed to the vibration but slowly loses its natural capacity, so that deafness, more or less complete, is gradu ally established.
Another effect of repeated concussion in these workers, and in others who use the hammer in rapid smart strokes, is a vibration along the nervous cords passing from the hand to the brain. The concussion gives rise to a thrill which amounts in time to pain and numbness, ending in failure of readiness to hold or grasp the hammer. When this symptom is established it, usually, continues, and often renders the workman unable to follow his occupation.
The series of vibrations produced in railway travelling are not unfrequently severe in their results. In this mode of travelling there are several kinds of vibrations which tell upon the traveller. There is the shrill whistle at the railway station, which affects, through the organ of hearing, the whole of the nervous system. There is the vibration produced by the rolling of the carriages and the collisions of one carriage with another in stopping; and, there is the constant vibration which is felt from the mere motion of the carriage as it rolls along.
By all railway travellers these symptoms are more or less ex perienced at first, but after a time, when travelling is very fre quently repeated, they seem to pass away, as if the senses and sensibilities were deadened to them from use. It may be that in certain constitutions the bad effects are actually neutralized by habit, but it is more common that they are only concealed. In many persons, such as commercial travellers, guards, drivers, and stokers of the engines, who are the persons more particularly con cerned, there is experienced after a time, if they are to suffer from the vibration, a sensation of thrill which extends along the spine, and which is uncomfortable if not actually painful. When this sensation is borne for several months or years, which is often the case, the digestive functions begin to fail, dizziness with frequent headaches supervene, followed, in the more determinate examples of disease, by want of power and by numbness in the lower limbs, with uncertainty of position and of pressure when the foot is brought to the ground. If the symptoms be noticed in time and promptly met they generally subside under rest and judicious treatment, but I have known them pass into complete failure of muscular power with premature break up of life.
Young children are often severely affected by the vibratory shrieking and tumult at the railway station.
More determinate and sudden concussions and shocks are in flicted on railway travellers by the severe collisions, which now and then occur. Under such concussions, though there may be no trace of actual physical injury, the nervous systems receive, some times, a shock so severe that it is never recovered from, or, if it be recovered from, only after a long interval of time. In some in stances the ganglionic nervous system is the part that receives the shock, when the stomach and other digestive organs specially suffer. A sorter of letters in a mail van felt that the train was off the rails, and the van going at great speed down a decline. He seized a rope that was hanging from the centre of the van, hung by it, saved the direct shock which came, and showed no sign of bruise or blow. But he " spun round," as he expressed it, " like a top," and when he found his legs again was suffering an intolerable pain in his stomach and bowels, with violent attempts at vomiting. He came under my care almost immediately afterwards, and though the pain subsided, the effects of the shock to the organic nervous sys tem remained persistent. He lost all digestive power, suffered from continued intermittency of the heart, became emaciated, and finally succumbed. In other instances of shock the spinal cord is the part impressed, and want of power or actual failure, paralysis, of some of the groups of muscles supplied by the cord succeeds, although no visible physical injury has been inflicted. I have known an instance of this kind in which paralysis of the lower limbs lasted for ten years, and may possibly have continued longer, for the affected person, although I have lost sight of him, may be still alive.
In a third class of cases of concussion the brain is the organ that sustains the shock in one or other of its parts, upon which various kinds of cerebral symptoms follow, such as giddiness, nausea, noises in the head, irregular muscular movements amount ing sometimes to epileptic seizure, or failure of nervous power. One common impression made upon the brain from these is that of sense of repetition of the concussion followed by great excitement. In such cases various exciting causes will light up the panic. A little noise when falling asleep will be all suffi cient. The hearing of a crash or fall, the rattle of a train, or car riage, will be all sufficient. In the worst illustration of the kind the mere news or recital of an accident will light up the record of the impression with all its excitements and dreads, and will be followed with after excessive depression and local or general failure of nervous power.
The phenomena of sea-sickness may no doubt be placed under this same head in relation to cause. The effect of the motion of the vessel is to produce a series of shocks both to the ganglionic, or organic, as well as to the cerebro-spinal system. In some per sons the organic nervous system is chiefly affected. They are easily made to vomit, and suffer as severely for the time as the patient of whom I spoke above who suspended himself by the cord in the railway carriage. They are slow to recover from the sickness; they lose appetite, and remain prostrate for many weeks, perhaps as long as the voyage lasts, and I have known at least one instance in which the sickness was never entirely recov ered from during a comparatively long life. In other persons the shock tells most upon the brain and spinal cord. They are less troubled with vomiting, but are oppressed with headache, giddi ness, and inability to stand upright or move with steadiness. After they have completed the voyage these persons suffer still from unsteadiness in walking, feeling, as they express it, the movements of the vessel. On going to sleep they are for a time conscious of the same phenomenon, and are awakened by it, as if experiencing the pitching of the vessel. A repeated series of con cussions have, as it were, affected the brain so as to leave an im pression of a wave-like motion which does not subside until after a considerable length of time.
There are other kinds of concussion which determinately affect the heart and the circulatory system, as well as the nervous organism. The carpenter, who, by the way, enjoys a moderately healthy life, his rate of mortality being as ninety-one to the mean of a hundred of the other occupations, is subject to a concussion of a special kind from planing wood. This concussion extends through the chest, and causes a peculiar condition in the large artery, the sub-clavian, which runs under the collar-bone, so that if the stethoscope be placed over the artery, the pulsation of it is sure to be accompanied by a murmur of a harsh character. In course of time the effect of this concussion is felt also by the heart. The action of the heart becomes disturbed, irregular, and enfeebled. A similar state of things is induced in the wood-saw yer, in whom indeed the jerk connected with the act of sawing is brought to bear more distinctly and rapidly upon the heart.
Persons who have to ride much on horseback, and soldiers, such as artillerymen who ride on the gun-carriages, are subject, in like manner, to concussion, which is felt not only by the heart, but by the great blood-vessel which ascends from the heart, the ascending aorta. I have already explained at page 143 that in the old posting days aneurism of the aorta was so common among post-boys from this cause, that it was called " post-boy's disease." The mode in which this concussion tells upon the heart is ob vious enough. The whole column of blood from the right ven tricle has first to ascend through the aorta. It is prevented find ing its way back into the ventricle by the semilunar valves which lie across the orifice of the vessel; but in riding, with each bump upon the saddle, as it is called, the ascending column of blood is brought slightly back, by the concussion, upon the valves. This causes undue pressure upon the valves and undue pressure, from within, upon the artery itself. The artery thus becomes gradually dilated, loses its elasticity, and is made the seat of the aneurisms] affection. For these reasons almost all men who ride hard and long suffer from enlargement and failure of the aorta, if not from aneurism.
The effects of concussion may be so severe, in exceptional in stances, as to cause a fatal accident in the way above described. The late Mr. Bloxam, of Duke Street, for many years my col league, consulted me once in a case of this kind which led to an inquest. A plumber fell from a height, while doing some repairs to a window, and dropped direct upon his feet. He died shortly afterwards. We found that the cause of death was a small tear or rupture of the aorta, just above the aortic valves. The valves being closed at the moment of shock, the blood came down upon them, like the water hammer in the water pipe when the water comes down on the closed tap, and the vessel gave way.
Porters who carry heavy burdens, and waiters who carry weights up and down long flights of stairs, are exposed to the same dangers; and, in a more gradual but hardly less certain way, our steady and useful friends the postmen are similarly debited with disease from concussion.