Fig. 79.—Circulation in the Capillaries, as seen with the Microscope.
As the pulse varies much in its rate and character in disease, it is to the skilled touch of the physician an invaluable help in the diagnosis of the physical condition of his patient.
Experiment 92. To find the pulse. Grasp the wrist of a friend, pressing with three fingers over the radius. Press three fingers over the radius in your own wrist, to feel the pulse.
Count by a watch the rate of your pulse per minute, and do the same with a friend’s pulse. Compare its characters with your own pulse.
Observe how the character and frequency of the pulse are altered by posture, muscular exercise, a prolonged, sustained, deep inspiration, prolonged expiration, and other conditions.
197. Effect of Alcoholic Liquors upon the Organs of Circulation. Alcoholic drinks exercise a destructive influence upon the heart, the circulation, and the blood itself. These vicious liquids can reach the heart only indirectly, either from the stomach by the portal vein to the liver, and thence to the heart, or else by way of the lacteals, and so to the blood through the thoracic duct. But by either course the route is direct enough, and speedy enough to accomplish a vast amount of ruinous work.
The influence of alcohol upon the heart and circulation is produced mainly through the nervous system. The inhibitory nerves, as we have seen, hold the heart in check, exercise a restraining control over it, very much as the reins control an active horse. In health this inhibitory influence is protective and sustaining. But now comes the narcotic invasion of alcoholic drinks, which paralyze the inhibitory nerves, with the others, and at once the uncontrolled heart, like the unchecked steed, plunges on to violent and often destructive results.
Fig. 80.—Two Principal Arteries of the Front of the Leg (Anterior Tibial and Dorsalis Pedis).
This action, because it is quicker, has been considered also a stronger action, and the alcohol has therefore been supposed to produce a stimulating effect. But later researches lead to the conclusion that the effect of alcoholic liquors is not properly that of a stimulant, but of a narcotic paralyzant, and that while it indeed quickens, it also really weakens the heart’s action. This view would seem sustained by the fact that the more the intoxicants are pushed, the deeper are the narcotic and paralyzing effects. After having obstructed the nutritive and reparative functions of the vital fluid for many years, their effects at last may become fatal.
This relaxing effect involves not only the heart, but also the capillary system, as is shown in the complexion of the face and the color of the hands. In moderate drinkers the face is only flushed, but in drunkards it is purplish. The flush attending the early stages of drinking is, of course, not the flush of health, but an indication of disease.[[34]]