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Take a Davidson or Household rubber syringe. Sink the suction end into water, and press the bulb. As you let the bulb expand, it fills with water; as you press it again, a valve prevents the water from flowing back, and it is driven out in a jet along the other pipe. The suction pipe represents the veins; the bulb, the heart; and the tube end, out of which the water flows, the arteries.
When the arteries are, as the doctor puts it, "as hard as pipe-stems," they grow in a few weeks, sometimes in a week, soft and pliable. The change, according to Dr. Brinkley, is brought about in the walls of the arteries themselves, and is not a process of dissolving the accumulations or deposits of calcareous material within the arteries.
The other kind of stimulus may be compared to disagreeable sensation, or aversion, as when the heart has received the blood, and is stimulated by it to push it forwards into the arteries; the same again stimulates the arteries to contract, and carry forwards the blood to their extremities, the glands and capillaries.
“The ball did not penetrate the brain,” he said, as he finished, “nor do I think the skull is injured, although the ball plowed along it for some distance. Fortunately it was a small bullet, one from a revolver, probably, which hit him. It cut a number of small arteries in its course, and that is the reason he has bled so much. An hour more and he would have been beyond my skill.”
We shall certainly be two days without water or pasturage for the cattle, but they are in such good condition that they will not much feel it. There is a river which we shall cross near its head, but the chance of water is very small; indeed, I believe we shall find it nowhere, except in these great arteries, if I may so call them."
Meantime the arteries continue to press the blood along until the veins become swollen. Then, as soon as the muscle ceases its contraction, the blood flows faster from the previous accumulation. If, then, we use a number of muscles, and use them strongly and quickly, there are so many veins affected in this way as to quicken the whole circulation.
She appears to revel in grim details of arteries and ligaments. The fact is, she is restless and wants some occupation, and this seems to appeal to her." "I believe I know how she feels. I went through something the same experience, my last year in college," Billy said thoughtfully. "It is a species of mental growing pains; one wants to do something, without knowing just what.
Again, in those animals the ventricles of whose hearts are smooth on their inner surface, without villi or valves, and the walls of which are thin, as in fishes, serpents, birds, and very many genera of animals, the arteries differ little or nothing in the thickness of their coats from the veins.
There was little or no sclerosis visible in the secondary arterial branches and but few patches in the larger arteries. Microscopically the cortex proved to be far from normal: every area examined showed cell-loss, perhaps more markedly in the suprastellate layers than below. Mental symptoms of a pronounced character are said to have begun at 75. Death at 80.
Another bad effect from the use of much alcohol is the weakening of the heart through the accumulation of fat around this organ and within the heart muscle. The use of alcohol also leads in many cases to a hardening of the walls of the arteries, such as occurs in old age. This effect makes the use of alcohol especially dangerous for those in advanced years.
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