In ordinary health the circulation of the blood in the brain follows in order the general circulation. Anything that increases the flow generally will increase the flow of blood in the brain. Anything that excites the heart action increases the amount of blood passing through the brain. Active hyperemia must occur under many circumstances and conditions, and there are no symptoms further than prominent veins on the forehead and temples and a full feeling of the arteries. When this is brought about by a plethoric habit--from eating rather more than is necessary--there will be no symptoms until the habit of overeating has been maintained for several years. Then, when such subjects lie down, there will be a purplish appearance of the skin around the eyes, nose, and ears; and when they stoop, over, the face gets very full of blood and quickly turns purple at different points. Such subjects may boast of excellent health and lots of strength; but they are developing such a state of dilation of the blood vessels of the brain, and perhaps the upper part of the spinal cord, that apoplexy is invited. If their blood is suddenly reduced by an accident which opens the blood vessels and allows a great loss of blood, there is danger of a sudden collapse. By this I mean that a surplus amount of blood is drawn off so quickly that it leaves the brain anemic, and the shock may be so sudden as to cause death long before the patient has lost sufficient blood to account for it.

If such patients are prostrated on a bed of sickness until quite anemic, there is danger of death coming from anemia of the brain. In truth, it would be a case of bleeding oneself to death in his own veins. It is dangerous for any one organ of the body to be kept in a state of hyperemia running over a long period of time.

Consciousness is kept in evidence by a continuous supply of blood to the brain. When the brain is suddenly made anemic, patients fall in a faint. When patients suffer from oxygen starvation, brain efficiency is lost. It requires a full amount of rich arterial blood to keep up mental efficiency. Under the influence of emotion, the action of the vasomotor nerves is cut off, and, as a consequence, the abdominal blood vessels become distended with blood. The blood pressure falls and the heart falls; in other words, the heart empties, the circulation of the brain falls, and unconsciousness occurs. This will happen when a large ovarian cyst is removed from the abdomen, or a large accumulation of dropsical fluid is drawn off suddenly. Where these accumulations are removed suddenly, patients are liable to bleed to death within their own bodies. The blood vessels of the abdomen have been pressed upon until paralyzed; then, when the pressure is removed, they are filled, with no power to empty.

When using chloroform on patients, it is necessary to have them in a horizontal position; otherwise the anesthesia is liable to kill them. The reason for this is that the chloroform partially paralyzes, or in truth does paralyze, the muscular coats of the arteries. The blood empties into the abdomen from the brain, and the patient dies from fatal syncope. Only the foolhardy would attempt to give chloroform to patients in a sitting posture. A half-sitting position is dangerous, This is often the position that patients are in when dentists work upon the teeth. I have had considerable to do with anesthetizing patients, but I have always insisted upon the horizontal position. If, however, this is not possible--if the dentist is not expert enough to operate upon his patient in that position--then the chloroform should be given according to my hasty method; namely, have the patient breathe deeply and rapidly, with the face under a towel, for about two minutes. Then add chloroform, and allow the patient to inhale rapidly for about one minute. Then remove the chloroform, and let the operation take place. If the dentist is expert, he should pull several teeth before the patient has any real sense of pain. Under such circumstances there is no danger of collapse or heart failure. A weak heart--made so by various causes--may have the influence of keeping the brain anemic. I have found that patients who have a very slow pulse, running from thirty to fifty to the minute, usually carry a state of hyperemia at the base of the brain, which will not be suspected. It is a condition brought on from overeating, causing more or less plethory. If these patients are fasted for three or four days, the volume of blood is let down; there will be a feeling of dizziness in the head on account of the loss of pressure from the hyperemia, and they will complain of a feeling of heaviness, closely bordering on dizziness--all due to the fact that there is a sort of collapsed state of the blood vessels.

If such a patient is fed very carefully, and not enough to raise the blood pressure--just enough to keep body and soul together--an adjustment will take place in the blood vessels of the brain, so that after a while--in the course of a few weeks--the food may be increased in amount, and eventually the patient can eat all that is necessary, and continue to have a pulse at from sixty-eight to seventy-four--the normal pulse-rate; whereas for perhaps ten years or more before there had been a pulse never rising as high as sixty. If this condition is not recognized and corrected, such patients will die of apoplexy; or there will be an increasing hyperemia that may continue to inhibit the circulation until there is death from heart paralysis.

Heart weakness may be brought on from any habits that overstimulate and bring on enervation. Some people are more liable to take on heart weakness than others. There is a predisposition--or it would be better to say a special diathesis--and they take on derangements more easily than others. The gouty diathesis will develop rheumatic heart trouble.