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The Effect of Alcohol upon the Blood. It has recently been discovered that alcohol has an extremely injurious effect upon the colorless corpuscles of the blood, lowering their ability to fight disease germs to a marked degree. This is well seen in a comparison of deaths from certain infectious diseases in drinkers and abstainers, the percentage of mortality being much greater in the former. Dr. T. Alexander MacNichol, in a recent address, said :

"Massart and Bordet, Metchnikoff and Sims Woodhead, have proved that alcohol, even in every dilute solution, prevents the white blood corpuscles from attacking invading germs, thus depriving the system of the coöperation of these important defenders, and reducing the powers of resisting disease. The experiments of Richardson, Harley, Kales, and others have demonstrated the fact that one to five per cent of alcohol in the blood of the living human body in a notable degree alters the appearance of the corpuscular elements, reduces the oxygen bearing elements, and prevents their reoxygenation."

Emphasis is frequently placed on the destruction and deterioration of the leucocytes or white blood corpuscles by writers on the subject. Dr. Grosvener declares:

"The poisoning and paralyzing influences of alcohol lead to the conclusion that the alcoholized organism presents a lessened resistance to the attacks of microorganisms. The detailed experiments of Abbot upon lower animals lean strongly toward the same conclusion. His experiments upon rabbits showed that the normal vital resistance to some organisms was markedly diminished.

"Rubin as reported in Journal of Infectious Diseases, May 30, 1904, studied the effect of alcohol upon infectious disease as shown in rabbits. He found that the number of leucocytes was much less in alcoholized than in the control rabbits, that as soon as the leucocytes began to decrease the bacteria increased, that there existed a negative chemotoxis."

Alcohol in the stomach is rapidly absorbed and passes into the blood stream. There the strong affinity of alcohol for oxygen, which leads them to enter very rapidly into chemical combination, causes the alcohol to appropriate the oxygen of the red corpuscles of the blood, which, as we have seen, are the great oxygen carriers in the body. This tends to impoverish the blood and render it less valuable to the tissues. Macy, Physiology.

Alcoholic drinks

The Effect of Alcohol on the Circulation. affect the very delicate adjustment of the nervous centers controlling the blood vessels and heart. Even very dilute alcohol acts upon the muscles of the tiny blood vessels, consequently, more

blood is allowed to enter them, and, as the small vessels are usually near the surface of the body, the habitual redness seen in the face of hard drinkers is the ultimate result.

As a result of experiments performed in 1869, Zimmerberg declares: "In the light of these experiments one is not only justified in denying to alcohol any stimulating power whatever for the heart, but, on the contrary, in declaring that it lowers the working capacity of that organ."

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Dr. J. H. Kellogg, head of the Battle Creek Sanitarium, says: The full bounding pulse usually produced by the administration of an ounce or two of brandy properly diluted, gives the impression of an increased vigor of heart action; but it is only necessary to determine the blood pressure by means of a Riva-Rocci instrument, or Gaertner's tonometer, to discover that the blood pressure is lowered instead of raised. This lowering may amount to twenty or thirty millimeters, or even more. . . It can readily be seen, then, that the bounding pulse is not the result of increased heart vigor, but indicates rather a weakened state of the heart, combined with a dilated condition of the small vessels."

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In an address before the Liverpool Medical Association, Dr. James Barr, president of the association, discussing the effects of medicinal doses of alcohol upon the circulation, remarked: "It causes dilatation of the arterioles and of all arteries well supplied with muscular fibers, owing to its paretic effect upon the vasomotor nervous system, and its direct action as a protoplasmic poison on the muscular fiber. It has a similar, though less marked, action on the cardiac muscle. From these causes the systolic blood pressure is lowered, the systolic output from the heart is diminished, and the cardiac energy is wasted in pumping blood into relaxed vessels; the large bounding pulse with comparatively short systolic period, which gives a deceptive appearance of vigor and force in the circulation, is due to the large wave in the dilated vessels."

"The first effect of diluted alcohol is to make the heart beat faster. This fills the small vessels near the surface. A feeling of warmth is produced which causes the drinker to feel that he was warmed by the drink. This feeling, however, soon passes away, and is succeeded by one of chilliness. The body temperature, at first raised by the rather rapid oxidation of the alcohol, is soon lowered by the increased radiation from the surface.

"The immediate stimulation to the heart's action soon passes away and, like other muscles, the muscles of the heart lose power and contract with less force after having been excited by alcohol." Macy, Physiology.

Alcohol, when brought to act directly on heart muscle, lessens the force of the beat. It may even cause changes in the tissues, which eventually result in the breaking of the walls of a blood vessel or the plugging of a vessel with a blood clot. This condition may cause the disease known as apoplexy.

Effects of Tobacco upon the Circulation. "The frequent use of cigars or cigarettes by the young seriously affects the quality of the blood. The red blood corpuscles are not fully developed and charged with their normal supply of life-giving oxygen. This causes paleness of the skin, often noticed in the face of the young smoker. Palpitation of the heart is also a common result, followed by permanent weakness, so that the whole system is enfeebled, and mental vigor is impaired as well as physical strength." Macy, Physiology.

XXVII. RESPIRATION AND EXCRETION

Problem LI. A study of the organs and process of respiration. (Laboratory Manual, Prob. LI.)

(a) Organs of respiration in frog.

(b) Mechanics of respiration.

(c) Process of respiration in the lungs.

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Necessity for Respiration. We have seen that plants and animals need oxygen in order that the life processes may go on. Food is oxidized to release energy, just as coal is burned to give heat to run an engine. As a draft of air is required to make fire under the boiler, so, in the human body, oxygen must be given so that foods or tissues may be oxidized to release energy used in growth. This oxidation takes place in the cells of the body, be they part of a muscle, a gland, or the brain. Blood, in its circulation to all parts

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glottis, and into the windpipe. This cartilaginous tube, the top of which may easily be felt as the Adam's apple of the throat,

From

pulmonary
artery

Bronchial

Tybe

To pulmonary

vein

divides into two bronchi. The bronchi within the lungs break up into a great number of smaller tubes, the bronchial tubes, which divide somewhat like the small branches of a tree. This branching increases the surface of the air tubes within the lungs. The bronchial tubes, indeed all the air passages, are lined with ciliated cells. The cilia of these cells are constantly in motion, beating with a quick stroke toward the outer end of the tube, that is, toward the mouth. Hence, if any foreign material should get into the windpipe or bronchial tubes, it will be expelled by the action of the cilia. It is by means of cilia that phlegm is raised from the throat. Such action is of great importance, as it prevents the

Air

Oxygen

Carbon

dioxide

Water

Air

Heat

Other wastes

filling of the air passages with Diagram to show what the blood loses and foreign matter. The bronchi

gains in one of the air sacs of the lungs.

end in very minute air sacs called alveoli, -little pouches having elastic walls, into which air is taken when we inspire or take a deep breath. In the walls of the alveoli are numerous capillaries, the ends of arteries which pass from the heart into the lung. It is through the very thin walls of the alveoli that an interchange of gases takes place which results in the blood giving up part of its load of carbon dioxide, and taking up oxygen in its place.

The Pleura. The lungs are covered with a thin elastic membrane, the pleura. This forms a bag in which the lungs are hung. Between the walls of the bag and the lungs is a space filled with lymph. By this means the lungs are prevented from rubbing against the walls of the chest. Breathing. In every full breath there are two distinct movements, inspiration (taking air in) and expiration (forcing air out). In man an inspiration is produced by the contraction of the muscles between the ribs together with the contraction of the diaphragm, the muscular wall just below the heart and lungs; this results in pulling down the diaphragm and pulling upward and outward of the ribs, thus making the space within

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