In order to obtain the best hygienic condition of the circulatory system, it is indispensable to avoid all that are harmful to the adrenals. There can no longer be any doubt that these glands exercise a controlling influence on the heart and the whole circulatory system. They are in intimate relation with the principal nerves that regulate the heart: the sympathetic and the vagus. Thus, for instance, emotions that act on these nerves excite through them a hypersecretion of the adrenals and a contraction of the small blood-vessels, with a rise in the blood-pressure. By the hyperactivity of these glands their secretion, in larger quantity than usual, is thrown out into the system, producing toxic effects which result in an atheromatous condition of the arteries. According to our present knowledge, we imagine this atheromatosis to be due to the toxic effect of the adrenals quite independently of the increase in the blood-pressure, for it has been distinctly shown that even substances which diminish blood-pressure, such as amyl nitrite, for example, are also capable of producing atheroma. The toxic effects of adrenalin are proved by the experiments of Amberg[200] in the laboratories of the Johns Hopkins University.
We must especially insist on the fact that high blood-pressure is not a condition essential to arteriosclerosis. It has been shown by Sawada,[201] Groedel,[202] and Ferranini,[203] through measuring the blood-pressure by Riva-Rocci’s instrument, that numerous cases of arteriosclerosis can arise without any increase at all in the blood-pressure. According to Professor Romberg,[204] there is only high blood-pressure in such cases of arteriosclerosis where there is a diseased condition of the kidneys. According to this leading authority on heart diseases, high blood-pressure is one of the earliest symptoms of kidney complication in arteriosclerotic persons. We believe that the high blood-pressure found in kidney diseases may be brought into correlation with the previous statement, by the fact that in such conditions, and especially in sclerosis of the kidneys, the adrenals, if examined, are frequently found to be hypertrophied, as was noted by Parkes Weber,[205] Lemaire, and in four cases of Troin and Rivet.[206] At the last Congress of German Physicians and Naturalists in Dresden, 1907, it was proved by Schur and Wiesel, as also in their previous communications, that the blood of patients affected with kidney diseases contained the characteristic substance that gives the adrenalin reaction with perchloride of iron, and produced mydriasis if dropped into a frog’s eyes.
It is of singular interest that all those agencies that produce a hypersecretion of the adrenals are the same which are known to be harmful in causing arteriosclerosis. In the front rank of such are tobacco, alcohol, and different kinds of poison, such as lead, mercury, etc.; also infectious diseases, especially syphilis, the important rôle performed by which, in the production of arteriosclerosis, has been treated of very competently by Professor Edgreen,[207] of Stockholm, and Darier, of Paris. Arteriosclerosis can also be produced very frequently by abundant meat food and by strong tea or coffee. There is as yet no scientific proof to show that abundant meat food has the same deleterious action on the adrenals as upon the thyroid, ovaries, pituitary body, pancreas, liver, kidneys, etc., upon which we have enlarged in previous chapters of this book; and, moreover, we have no knowledge of any work written on this subject; but as such a diet is very efficacious in producing a sclerotic condition of the kidneys, it may, for these reasons alone, tend to further the development of arteriosclerosis, considering that so often in such conditions both kidneys and adrenals are found in a hypertrophic condition. This disease may be produced by alcohol, tea, and coffee, by causing a great variation in the tone of the capillaries. According to Professor Romberg and others, it remains to be proved whether they affect the adrenals at all; but we have already shown what their action is on the kidneys.
To keep the adrenals in good condition and thus prevent arteriosclerosis, it is necessary to avoid all the above harmful agencies. It is true that there are some people who can enjoy these things in large quantities with impunity and without injurious effects until they reach a considerable age; but it is different when they all act together. Especially deleterious are mental emotions, grief, and sorrow, on which we have dwelt in the introduction to this chapter, and on the effects of which we have previously remarked; they produce a great variation in the tone and calibre of the blood-vessels. We will therefore endeavor to treat of the prevention of a prolonged continuance of this most disastrous agency in our chapters on the hygiene of the mind. Emotions of a sexual character are, perhaps, more than emotions from other sources, disastrous to the heart and blood-vessels, as shown by the fact, which may often be observed, that persons addicted to sexual excitations frequently die from sclerosis of the coronary arteries. That the sexual glands are in intimate relations with the heart, which can often be irritated in consequence of changes in these glands, especially in women, has been already mentioned.
We should like to add that, as the above agencies are also harmful to the thyroid gland, the antagonist of the adrenals, its degeneration can further the development of arteriosclerosis in the same way that Eiselsberg produced an atheromatosis of the aorta in dogs after extirpating the thyroid gland. According to Minnich, arteriosclerosis is very common in people with goiter, appearing in them at a very early age. Fries and Pineles found that alterations of the blood-vessels occurred in goats after extirpation of their thyroid gland.
Since arteriosclerosis is so frequent in old age it must be due to the degeneration of the thyroid and also to the aggregation of all the above-named harmful agencies during a prolonged period. To avoid it, and also premature old age, it is, therefore, most essential to guard against all agencies harmful to the thyroid and adrenals, to which we have referred above; and this is the best basis for the rational treatment of arteriosclerosis. It is most fortunate that Dellamare discovered in old age a hypertrophy of the adrenals.[208]
All this is greatly strengthened by the recent investigations of Sajous, which show that besides its action on the blood-pressure and the heart, the adrenal secretion actually supplies the substance which in the lungs, takes up the oxygen from the air to sustain life in all our tissues. It thus becomes evident that harm to our adrenals is bound to shorten life.
To recapitulate: There exist two chief agencies for the production of arteriosclerosis: 1. A hyperactivity of the adrenals, causing a rise in blood-pressure. 2. A degeneration of the thyroid gland, which, when normal, antagonizes the first by lowering the blood-pressure. Although from the above-mentioned facts high blood-pressure cannot be considered as the chief cause of arteriosclerosis, still no doubt it certainly contributes to it; for each time that there is a rise in the blood-pressure more blood is forced through the arteries, thereby causing them to dilate; and after a repeated number of such dilatations the elasticity of the vessels will eventually be impaired, especially so in the aged, where one part of the elastic fibers is already replaced by connective tissue. As a result of the arteriosclerosis the passage of blood through the capillaries will be impeded, and in consequence the work of the heart will be increased; likewise the nutrition of the walls of the vessels will be diminished. The best preventatives of arteriosclerosis will therefore be: 1. To avoid all agencies which may tend to cause excessive activity of the adrenals; and 2. To increase the activity of the thyroid.
Moderation in food is necessary above all things, for much food causes an increase in the abdominal circulation and a larger amount of blood to be carried through the vessels; if the food consists of much meat, then its viscosity is augmented, as previously stated, which indicates that a vegetable diet, with milk, and little or no meat, is the best; but too large quantities of milk should not be taken at one time.
Much bodily and other exercises, in excess, such as too much climbing, should be avoided, as they promote arteriosclerosis by frequent excitation of the splanchnics and adrenals. As Romberg observed, there is sclerosis of the arteries in the extremities of persons who do much physical labor, and Remlinger[209] found the same in the lower extremities of peasant women who walked a great deal.
Not only by a diet, chiefly vegetarian, is the viscosity of the blood diminished and the circulation facilitated as found by Determann, but also by means of iodine administered in the shape of iodide of potassium or iodide of sodium. This has been proved by the experiments of Ottfried, Müller, and Inada.[210] For many years it has been well known that iodine can greatly benefit the condition of arteriosclerotic persons. In combination with a preparation of iodine, Professor Senator[211] favors the use of nitrites, and Professor Huchard also recommends nitroglycerine in the intervals between the iodide treatment. Besides inorganic iodine, it would appear to us logical to try organic iodine preparations, such as thyroid extracts, the principal element of which is iodine. For the above reasons it is also necessary to take special care of the condition of the kidneys, which can be done, as we have shown, by hygienic and dietetic measures, already described in the special chapters of this work. An improvement in the condition of the kidneys, and probably also in the arteriosclerosis, may, in our judgment, be obtained by the administration of kidney extracts, with which we will deal more fully in the chapter on the treatment of old age by organic extracts.
According to Edgreen, about 25 per cent. of the cases of arteriosclerosis is caused by alcohol. It acts by causing a constriction of the small vessels (Traube), just as does adrenalin.
But much more harmful in the production of arteriosclerosis is tobacco. According to Claude Bernard, Huchard, Basch, Oser, Isaac Adler, and Hensel, tobacco produces a constriction of the small blood-vessels. Thus nicotin, adrenalin and alcohol have similar actions, which also corresponds to the observations of Sir Lauder Brunton. We have had a great many smokers among our arteriosclerotic patients; but, on the other hand, we quote further on the cases of some great smokers who lived to a very old age as we have seen. But this latter class is not numerous.
Similarly, the hygiene of the intestines is of the utmost importance, especially as poisons generated in the intestines play a leading part in causing arteriosclerosis, according to Huchard, Senator, and others. We must take great care to have a daily evacuation of the bowels, and especially to prevent flatulence, for this distention of the colon or the stomach, by carrying the diaphragm upward, may interfere with the expansion of the lungs and thus produce a mechanical hindrance to the movements of the heart and a free circulation of the blood. Those with a tendency to angina pectoris must specially avoid such dangerous courses. Hill climbing, during which not infrequently such people suffer sudden death, should also be avoided. More than from 1 to 1½ liters of liquids per day should not be allowed.