Page:Popular Science Monthly Volume 6.djvu/727

Rh. In fact, the evidences of impairment by any bad habit are seldom apparent during the prime of youthful vigor. But the mischief is going on nevertheless, and the organ upon which the weight of infringement falls will be the one that will first manifest signs of disease, and through which death will make its conquest over the body.

Besides this weakening of the vessels upon which the strong impulse of blood from the heart falls at the rate of sixty times a minute, and the very little external support such defective vessels receive from the soft and pulpy brain, there is another source of danger by a break, in the extraordinary ebbs and tides of blood to which the contents of the cranium are subject. During sleep the brain is almost bloodless; its substance seems to shrink into a lifeless mass; but the moment that wakefulness occurs it swells out, gets red, its arteries and veins becoming distended with a great tide of blood. No other part of the body is subject to such droughts and floods in its blood-circulation. This inequality is yet further increased by severe mind-labor. The ardent student is well aware that deep thought heats the head and cools the feet. The brain is then receiving more than an ordinary supply of blood and the feet less.

The first apoplectic stroke, as a rule, is not a severe one. Sometimes the condition of the cerebral circulation is simply that of active congestion; but more commonly a little blood escapes by a tiny vent, the shock to the system slows and enfeebles the action of the heart, the distention of the ruptured vessel is thus lessened, the escape of blood ceases, and Nature, by means of a slight inflammation, heals the part torn, and in due time removes the blood-clot by absorption.

The process by which a weakened blood-vessel is ruptured by internal distention may be illustrated by observing the effect of attempting to force through an old water-hose attached to a fire-engine a large and rapid stream of water. The weakness of the hose is first shown by the escape of tiny jets of water; but by-and-by a larger vent occurs, allowing the water to escape in a flood. Just so it is with the progressive weakening with the blood-vessels in the brain—the escape of blood is at first small; then, under a greater tension than ordinary, a larger rent is made, allowing the blood to escape in hopeless profusion. It was probably these well-known features of apoplectic strokes that led the great Napoleon's medical adviser to make his celebrated reply in reference to this disease, of which the emperor stood in great dread: "Sire, the first attack is a warning, the second a summons, the third a summons to execution."

Those who have a family tendency to apoplexy and are desirous to escape it, will, of course, avoid all the causes above referred to, especially those which tend to destroy the elasticity and strength of the blood-channels in the brain, or, in other words, to weaken the structure and life of those parts. But suppose, as is too often the case, that the