Page:Popular Science Monthly Volume 33.djvu/208

196 course of their daily vocations than printers, who are as a rule not subjected to anything like a similar class of petty annoyances during their work, no matter how arduous it may be.

That after the liver and the heart the brain should be the next organ of the body which suffers most from the injurious effects of alcohol when taken in small quantities at a time is no more than what might be expected. Indeed, I think it is even less, seeing that alcohol acts injuriously upon nerve-tissues in three distinctly different ways: First, through its chemical action upon the blood; second, by disordering the liver's functions and causing the bile to accumulate in the circulation, and thereby poison the brain and nerves; and, third, by its accelerating the heart's action, and thus sending an increased supply of blood to the brain—every increase in an organ's blood-supply being associated with a corresponding increase in the functional activity of the organ.

The increase of the cerebral circulation consequent upon the increase in the heart's action from the imbibition of small quantities of alcohol acts prejudicially, however, upon the brain in yet another way—namely, by its causing an engorgement and dilatation of the cerebral arteries. For, seeing that Nicol and Mossop found that so small a quantity as two teaspoonfuls of absolute alcohol caused marked congestion of the retinal blood vessels—which derive their blood-supply from the same source as the cerebral vessels—it is natural to infer that even the small quantity of two teaspoonfuls of alcohol will induce the same amount of congestion in the branches of the blood-vessels within the cranium as it does in those immediately outside of it; and if so, seeing that the organ is confined within a limited space and surrounded on all sides by unexpansible ridged walls, by their engorgement and dilatation they must of necessity press injuriously upon the brain-substance. The pressure thus exerted on the nerve-cells and fibers will not only prevent their performing their functions properly, but at the same time interfere with their nourishment, and consequently lead to a degeneration of their constituents. The deleterious effects of congestion of the intercranial blood-vessels are rendered apparent to us in yet another way—namely, by the feelings of fullness or tightness of the head experienced by many persons after partaking of alcoholic stimulants. Moreover, it appears to me that the facts just alluded to afford a reasonable explanation of why it so often happens that persons who indulge in small quantities of spirits while engaged in arduous mental labor frequently suffer from a sudden mental breakdown, notwithstanding that the immediate effect of the stimulants had appeared to be beneficial to them by increasing their brain-power. My explanation of the cause of