Popular Science Monthly/Volume 18/December 1880/Indigestion as a Cause of Nervous Depression I
|←Domestic Motors I|| Popular Science Monthly Volume 18 December 1880 (1880)
Indigestion as a Cause of Nervous Depression I
By Thomas Lauder Brunton
By T. LAUDER BRUNTON, M.D., F.R.S.
TO most men who are engaged in intellectual work, an autumn holiday has become a matter of necessity, and is not to be regarded as a mere luxury. During eleven months of the year many who are engaged in brain-work systematically overtax themselves, trusting to the month's holiday to bring them again into proper working order. Formerly this was not the case. Men seemed to be able to go on, not only month after month, but year after year, without any vacation at all. The circumstances under which they lived were different from those which exist now. The very means which facilitate our holidays}}the network of railways which puts us into complete and easy communication with any part of the Continent of Europe, or the quick ocean-steamers which enable us to enjoy half of a six weeks' holiday on the other side of the Atlantic, as well as the telegraphic communications which will warn us in a moment, even at the most distant point of our travels, of any urgent necessity for an immediate return—all these are the very means which increase our labor during the greater part of the year. We live at high pressure; letters and telegrams keep us constantly on the qui vive; express trains hurry us miles away from home in the morning and back again in the evening, and the pressure of competition is so great that few men can afford either to take their work easily or to modify the constant strain of it by breaks of a day or two at a time. Wearied and exhausted, the hard-worked man goes off for his autumn holiday, and, if he can, will spend most of it in the open air, either yachting, walking by the seashore, strolling in the country, shooting on the moors, or climbing the Welsh hills or the Swiss mountains. After a month spent in any of these ways, the brain-worker comes back to town feeling himself a different man. Instead of his work being a slavery to him, as it was before he started, he feels it to be a pleasure; he gets through it with ease, and feels not only that the amount he can accomplish is greatly increased, but that the quality is also improved. Perhaps for a short time after his return he is hardly in a condition to do brain-work at all. He sits down to his desk, but feels cramped in the unaccustomed posture, and he would rather work off the superabundant energy within him in a long walk or a stiff climb than restrain it with difficulty to the simple task of driving a quill. After a week or two he settles down and works steadily along with comfort and ease for a couple of months or more, when he again begins to sink below par. His appre- hension is no longer so acute, his power of concentration is diminished, he can no longer fix his attention for any length of time upon one sub- ject without a severe effort. His mental vision becomes less perspicu- ous, his ideas succeed each other more slowly, and find expression with greater difficulty, so that he communicates his thoughts with less fluency and less clearness than before. His temper, too, undergoes a change. Instead of regarding the daily occurrences of life with equa- nimity, and making the best of what can not be helped, irritation so Blight as to be unfelt at other times provokes him to anger or peevish- ness, and even when he possesses sufficient self-control to restrain his feelings and prevent them from being manifested outwardly, to the annoyance of his friends or neighbors, the very effort of restraint seems to increase the internal irritation, until at last it either explodes in an ebullition of wrath on some comparatively trivial circumstance, or tells upon the digestion and nervous functions of the individual himself, diminishing the appetite or causing intense muscular weari- ness. In others, again, we find that along with or taking the place of irritability there is great mental depression. Everything is looked at from a gloomy point of view himself, his friends, and his surround- ings. He does not feel equal to his work; nothing that he does pleases him; he is apt to become distrustful of himself and jealous of others; apt to think that his friends are slighting him, or to fancy that he has offended them. Even when all external circumstances leave nothing to be desired, the unfortunate victim can not enjoy life. His mind is occupied Avith gloomy forebodings of miseries to come, or he becomes a prey to melancholy and depression without any apparent reason. This melancholy weighs most deeply upon him during the night, and if he happens to wake in the small hours of the morning, as he not unfrequently does, life seems not worth living, but a burden of which he would willingly be quit. Melancholy is at times associated with sleeplessness, and then the two evils react upon and increase each other. For this causeless sorrow has a similar effect to that of real sorrow. As Shakespeare says:
"Sorrow's weight doth heavier grow, Through debt that bankrupt sleep doth sorrow owe."
At other times instead of sleeplessness there is an abnormal ten- dency to drowsiness, which sometimes comes on almost irresistibly at the very moment when some imj^ortant work, requiring all the best powers of the intellect, has to be performed, and rendering its perform- ance either imperfect or completely impossible. As soon as the person goes to bed he falls asleep, and sleeps like a log till morning, when he rises with difficulty, feeling more exhausted than when he went to bed the night before, with perhaps a little tightness or pain over the forehead, eyes, or temples. After breakfast he feels somewhat revived, and will work comfortably for a short time, but about one and a half or two hours after the meal weariness overtakes him, again passing off after it has lasted a variable time. During the day this is repeated, fits of more or less energy alternating with periods of lan- guor and exhaustion. These languid fits may be noticed two or three hours after lunch or dinner, and the sufferer is not unfrequently tempt- ed to have recourse to the decanter of sherry or the brandy-bottle, not only to obtain relief from the feeling of personal discomfort, but to supply the energy which he feels to be necessary to enable him to do the work he has in hand. But this is a ruinous course to adopt, for not only does it pave the way to habits of confirmed drunkenness, and leads to tissue-changes which will ultimately abolish the functional activity of the most important organs of the body, and bring the indi- vidual to a premature grave; it enables him to do his work only im- perfectly at the time. After an application to the decanter or bottle his powers may seem to himself to be as great as or greater than usual, but this is to a considerable extent a subjective feeling only, as he will probably be able to discover by results.
Now, how is it that such a change has come over the man in a few months, so that he seems to be a different individual from the one who returned, bright and lively, from his autumn holiday? How is it that the even-temj^ered man has become irritable, the clear-headed man muddled, the active lazy, the sober perhaps a tippler, and the cheerful and buoyant depressed and melancholy; that the brain performs all its functions with difficulty, and the mind is so altered that it does not seem to be that of the same individual? And yet, after all, the man is the same, and the brain is the same, at least in its essential structure, as it was a few months ago, and as it will be in a few months more, after another holiday has again put it in good working order. What has happened to it in the mean time to cause such a dreadful alter- ation? Not only does the brain seem exhausted, but the whole sys- tem appears to .be languid and weak; instead of the man being able for a twenty or thirty miles' walk, one of a mile or two will produce fatigue, and sometimes an intense languor is felt without any exertion at all. And yet all this time he may have been trying to keep up his strength. He takes butcher's meat three times a day, perhaps also strong soups, to say nothing of wine, or brandy-and-soda, to pick him up. His tissues ought to be getting sufficient nourishment to enable them to do their work, and yet it is evident that they are not in a condition to do so. The man, and very likely his friends also, wonders at his condition, and when he goes to his medical attendant to describe his case he says, "I take all sorts of strengthening things, and yet I feel so weak." If, instead of using these words, he were to say " Be- cause I take all sorts of strengthening things I feel so weak," he would express a part at least of the truth. He and his friends who wonder with him forget that all the functions of life are more or less pro- cesses of combustion, and that they are subject to laws similar to those which regulate the burning of the coal in our fireplaces. Two things are necessary for the combustion, fuel and oxygen; sometimes it is the fuel that fails, but not unfrequently it is the oxygen. Sometimes, no doubt, our fires go out because the fuel is quite exhausted, but this is very rarely the case. It is only under very exceptional circumstances that we find a fire burned away so completely as to leave nothing but ash. Almost invariably some fuel still remains often, indeed, enough to make up a good fire when properly put together. If we sift the ashes from the grate we generally find a quantity of cinders, sufiicient to make a fire, and these have ceased to burn because they were un- provided with oxygen, which was prevented from reaching them by the ashes with which they were covered.
The reason why our fires burn low, or go out altogether, either is that we put on too much coal, or that we allow them to be smothered in ashes. It is the child who pokes the fire from the top to break the coal and make it burn faster; the wise man pokes it from below so as to rake out the ashes and allow free access of oxygen. And so it is with the functions of life, only that, these being less understood, many a man acts in resrard to them as the child does to the fire. The man thinks that his brain is not acting because he has not supplied it with sufficient food. He takes meat three times a day, and beef -tea, to sup- ply its wants, as he thinks, and he puts in a poker to stir it up in the shape of a glass of sherry or a nip from the brandy-bottle. And yet, all the time, what his brain is suffering from is not lack of fuel, but accumulation of ash; and the more he continues to cram himself with food, and to supply himself with stimulants, although they may help him for the moment, the worse does he ultimately become, just as the child's breaking the coal may cause a temporary blaze, but allows the fire all the moi*e quickly to become smothered in ashes. It would seem that vital processes are much more readily arrested by the accu- mulation of waste products within the organs of the body than by the want of nutriment to the organs themselves. In all "cases of fasting, whether voluntary or compulsory, life is prolonged to a much greater extent if water be freely supplied. Without water the individual quickly dies, however much other nourishment he may get, but with abundance of water he may live for a considerable time, even if he take no solid nutriment at all. Here it is not that the water acts as a food; it supplies no new energy to the body, for, unlike starch, or sugar, or fat, or proteids, it has already undergone complete combus- tion. It can not, like them, unite any further with oxygen and thus supply energy.
And yet it is more essential to life than any of them, for without it the products of waste can not be removed from the tissues, and the vital fires, so to speak, are smothered in their own ash. If we take the excised muscle of a frog and stimulate it to repeated contraction, the contractions become feebler and feebler, until at last they cease alto- gether. But this is not because the fuel which the muscle contains in itself has been so completely burned up that none of it is left to fur- nish the requisite energy to the muscle; it is because the chemical pro- cesses necessaiy to the contraction of the muscle are arrested by the accumulation of the products of its own waste. If we wash these out of the muscle by sending through its vessels a weak solution of -com- mon salt, which supplies to it no new material, but which removes these waste products, the contractile power of the muscle will be re- stored.
This restoration takes place still more quickly and thoroughl}^ if we employ a fluid which will sixpply oxygen, such as a solution of per- manganate of potash, instead of a simple solution of salt, which merely washes out the muscular waste. The muscle is like a fire in the grate, which goes out long before the coal is entirely consumed, on account of the ash which smothers it, and just as we can revive the smoldering embers by supplying them with oxygen by the use of bellows, so the muscle revives more quickly when its supply of oxygen is increased. The quicker the fire burns the sooner will it be choked in ash, and the more rapidly the muscle contracts the sooner will it lose its powers.
The same is the case with the heart. The slowly beating heart of a crocodile will pulsate for a day or more after it has been cut out of the body, but the rapidly pulsating heart of a mammal will very soon cease to beat; and, the more rapidly it has been beating before the animal's death, the sooner will it cease to contract afterward. If the vagi are cut in the living animal so that the cardiac pulsations become excessively rapid, the heart's movement ceases almost as soon as the animal dies; but, if during life the vagi are irritated so as to make the heart contract very slowly indeed, it comes to resemble more nearly the heart of the crocodile, and continues to pulsate for a considerable time after the animal's death. The heart, too, resembles voluntary muscles, inasmuch as, if we wash out of it the products of its own waste, it will continue to beat for a much longer time than if we allow them to accumulate. By simply allowing a saline solution to circialate through the heart of a frog it may be kept beating for many hours longer than if it were left to itself. Both voluntary muscles and involuntary ones, such as the heart, cease to act, almost invariably, not by exhaustion of their energy -yielding substance, but by accumulation of the waste products within them; and muscles, both voluntary and involuntary, are much less sensitive to this process of choking than the delicate structures of the nerve-centers. The gastrocnemius, or the heart of a frog, may retain its irritability for very many hours after its sepa- tion from the body, but the spinal cord of the same animal will rarely retain its irritability for a single hour after the circulation through it has been arrested. In warm-blooded animals the spinal cord is much more sensitive than in the frog, and, if the circulation in the lower part of the spinal cord be arrested in a rabbit by the pressure of a thumb upon the aorta for three or four minutes, the hind-legs of the animal will become completely paralyzed. Still more sensitive than the spinal cord is the brain, and if the circulation in the latter organ be arrested, consciousness is almost instantaneously abolished. In the animal body as in the steam-engine, the governing and directing parts are much more sensitive and easily acted upon than the working parts. A sin- gle touch of the hand to the steam-valve will set the engine in action or stop its movement, although the power of a thousand men applied to the fly-wheel would avail little or nothing. And in animals the nerve- centers are most sensitive and respond most readily to those circum- stances which affect the organism. Not only are they exceedingly sensitive to the accumulation within them of the products of their own waste, but they are easily affected by alterations in the blood which circulates through them, and which conveys to them not only the prod- ucts of muscular and glandular waste formed in other parts of the body, but also substances introduced from without, or absorbed from the intestinal canal. A single whiff of nitrite of amyl is sufficient to dilate the blood-vessels; a fraction of a grain of pilocarpine will stim- ulate the sweat-glands to the most profuse secretion; and half a drop of pure hydrocyanic acid is enough almost instantaneously to abolish consciousness and destroy the functional activity of the entire nervous system. In the case of the nitrite of amyl, the pilocarpine, or the hydrocyanic acid, we are able to distinguish the relation of cause and effect between the administration of the drug and the resulting changes in the organism. We do this, however, because of our knowledge, obtained by observation and experiment. Sometimes we can not do this. I have seen, for example, a person become aware of a peculiar sensation which, to the patient, was quite unaccountable, but of which I understood the reason, as I knew it to be due to the fumes from a bottle of nitrite of amyl, which the patient could not see. We may notice a similar occurrence in poisoned animals. The poison of the cobra causes paralysis of the spinal cord and nerves, and induces in- tense weakness, so that the limbs of the animal fail under it, I have seen an animal in this condition attempt to walk, and look round at its legs with a puzzled air, as though it could not understand what was the matter with it. It could not connect the weakness in its limbs with the introduction of the poison some time previously, although the connection between them was to me perfectly clear. In the same way as the action of the cobra-poison was a mystery to the animal, an epidemic of typhoid fever was formerly to us a mys- terious occurrence for which no reason could be assigned, but we now trace it to the absorption into the bodies of the sufferers of typhoid poison introduced from without. We are now completely alive to the important results produced by the absorption from the intestinal canal of poisonous matters, such as typhoid-germs, arsenic, or strychnine introduced into it from without. But perhaps we are not yet suffi- ciently alive to the important results produced by the absorption from the intestinal canal of substances generated in it by fermentation or imperfect digestion. We recognize the danger of breathing gas from a sewer, but probably we do not sufficiently realize that noxious gases may be produced in the intestine, and, being absorbed from it into the circulation, may produce symptoms of poisoning. And yet we know, from recorded observations, that such is the case, and that one at least of the chief components of sewer-gas, viz., sulphuretted hydrogen, may be produced in the intestine. This gas, which is so readily recognized by its smell resembling rotten eggs, was found by Dumarquay * to be very quickly absorbed indeed from the intestine when injected into the rectum, and to be quickly excreted from the lungs, sometimes ap- pearing to produce, during its elimination, some inflammation of the tra- chea and bronchi. This was especially the case when small quantities were injected, and it seems not improbable that the production of this gas in the intestine may have something to do with the bronchitis which is not unfrequently observed in connection with digestive dis- turbance. In cases of indigestion this gas seems to be not unfre- quently formed, because persons often complain of the taste of rotten eggs in the mouth or in the eructations. Even in such small quanti- ties it is not improbable that it may exert a deleterious influence both upon the nervous system and upon the blood, for it is a powerful poison, in its action somewhat resembling hydrocyanic acid, though not so strong. It destroys ferments, and robs the blood-corpuscles and the seeds and roots of plants of their power to decompose peroxide of hydrogen; and, as this faculty seems to be closely associated with the processes of life, the sulphuretted hydrogen may be regarded as a powerful protoplasmic poison. Upon plants it has a curious action, differing very markedly from sulphurous acid. When plants are ex- posed to sulphurous acid, the leaves shrivel up, wither, and fall off, but, if the plant be now removed from the noxious influence of the gas and placed under favorable conditions, it will recover and send out fresh shoots. But, if it be exposed to the action of sulphuretted hydrogen, the leaves, instead of shriveling, simply begin to look flac- cid, and droop. This seems, at first sight, to be a less deadly action than that of the sulphurous acid, but when the leaves have once begun to droop in this way the plant is dead, and does not recover when re-
- " Comptes Rendus," ix, p. 724. moved from the action of the gas. This gas is rarely generated in the
intestine in such a quantity as to give rise to symptoms of acute poisoning, but it has sometimes this effect. A case is recorded by Senator * in which a strong and previously healthy man became af- fected with a slight gastro-intestinal catarrh in consequence of some error in his diet, and on the second day afterward he had frequent eructations, smelling strongly of sulphuretted hydrogen. At the same time he suddenly became collapsed, pale, giddy, and with a rapid, small, compressible pulse. This lasted for one and a half to two minutes, and then passed off. The urine which he passed shortly afterward contained sulphuretted hydrogen. On the same day he had a second attack of a similar sort, and then, the bowels having been opened, he recovered completely. Nor is sulphuretted hydrogen the only gas which may be formed in the stom&ch. Marsh-gas is sometimes formed there too, and, in an exceedingly interesting case recorded by Dr. Ewald,f the quantity was so great that it first attracted the patient's at- tention by taking fire as it issued from his mouth while he was lighting a cigar. In this curious case the formation of gas alternated with the production of a great quantity of acid fluid in the stomach, which led to vomiting, or, as the patient himself expressed it, sometimes his gas- factory and sometimes his vinegar-factory was at work. It is possible that this gas may be formed in small quantities in many more cases than has hitherto been suspected, but its absorption does not seem to have anything like the same deleterious action as that of sulphuretted hydrogen. Nor was the acetic acid which was found by chemical analysis to exist in the acid secretion of the stomach in this case likely to be productive of any injurious effects after its absorption. But butyric acid, which is sometimes formed in the stomach in other cases of indigestion, has been shown by O. Weber to be a powerful poison acting chiefly on the nerve-centers.
It seems probable, however, that the substances, both gaseous and solid, formed in the stomach and absorbed from it, are upon the whole less poisonous in cases of indigestion than those Avhich are produced lower down in the intestinal canal. We often find that patients are affected with severe gastric disorder without any affection of the nei-ve- centers beyond the weakness produced by the inability to digest food, while in many persons the mere omission to evacuate the contents of the bowels at the usual time will lead to a headache in the course of the day. No doubt such a headache as this may be due, to some ex- tent, to the nervous irritation caused by the presence of the faeces in the intestine, but it seems quite possible that it is also due to the ab- sorption of some of the faecal matter itself. Nor do we at present know what effects are produced by the absorption of the various diges- tive juices themselves. That such absorption takes place there can be
- " Berliner klin. Wochonschr.," 1868, No. 24.
f " Reicherts und Du Bois-Reymond's Archiv.," 18Y4, p. 217. little doubt. It has been demonstrated in the case of the bile, which is absorbed with great rapidity from the intestine and reexcreted by the liver, so that it does not pass into the general circulation at all. But what becomes of the other digestive fluids, and the ferments they contain? The pepsin finds it way in minute quantities through the liver, and has been discovered in various tissues of the body and in the urine. This, however, matters but little, for it can not act upon the tissues themselves, inasmuch as they possess an alkaline reaction. But the case must be somewhat different with pancreatine, and if pan- creatic fluid be absorbed from the intestine and pass through the liver unchanged, we should expect that it would have a very powerful action upon the tissues throughout the body, because there appears to be no reason why it should not act upon them just as it does upon the food in the intestine itself. It seems not at all unlikely, then, that the liver has got another function besides those usually assigned to it, viz., that of preventing the digestive ferments from reaching the general circulation so as to act upon the tissues. Now, we do find in the liver itself and in the bile a ferment having the same diastatic power as the pancreatic juice, but it does not appear in such quantities as one would expect if the whole of the pancreatic ferment were simply reexcreted by the liver along with the bile, and, as we have no evidence that the ferment is destroyed during its action in the intestine, we are naturally led to think that it may undergo a change in the liver, the converse of that which it undergoes in the pancreatic gland during the process of secretion. In the pancreas itself we have no ready formed ferment, but we have a ferment-forming substance, which has recently become known tinder the name of zymogen, given to it by Heidenhain, but the writer heard it described by Kiihne in his lectures on physiological chemistry delivered at Amsterdam in 1869. I quote verbatim from the notes which I took at the time of his lecture on the pancreas: "Glands which have no action on fibrine can be made active by di- gesting in very dilute acid and then neutralizing or alkalizing; there seeming to exist a ferment-forming substance in the pancreas." Dur- ing digestion this ferment-forming substance or zymogen splits up and yields free ferment, and it seems not improbable that it is in the liver that this very ferment, after its digestive work is done, becomes again converted into the ferment-forming substance which may circu- late throughout the tissues without doing them any injury.
Whether this be the case or not, however, with regard to the fer- ments of the gastric, pancreatic, and intestinal juices, all of which must pass through the liver before they reach the general circulation, there can be no doubt that the products of intestinal digestion do un- dergo very marked changes indeed in the liver, as is shown by the formation from them of very large quantities of a new substance, glycogen a substance which is not contained in the products of the gastric and intestinal digestion which reach the liver, and yet which is of the highest importance for the nutriment of the body. Under ordinary circumstances, nearly the whole of the sugar formed in the intestine and absorbed from it is arrested in the liver, so that very little passes into the general circulation and appears in the urine, although even in healthy persons traces of sugar are excreted by the kidneys. Under exceptional circumstances, however, sugar may pass through in considerable quantities, as, for example, when the individual takes, on an empty stomach, a large quantity of sirup. However healthy his organs may be, sugar will then appear in the urine. The same is the case in regard to albumen. Usually, the whole albumi- nous constituents of our food are so transformed in the stomach, intes- tines, and liver, that no albuminous substances of the kind which can pass through the kidneys get into the general circulation. But, if one takes such a quantity of eggs as to completely overtask the digestive powers, the egg-albumen will pass unchanged into the blood, and be excreted by the kidneys.
Other albuminous substances, the products of intestinal digestion, and peptones also, occasionally make their appearance in the urine, as well as egg-albumen. Even when the processes of assimilation are not so seriously interfered with as in these instances, we observe that products of nitrogenous waste frequently occur in the form of lithates in the urine. An excess of these indicates some pathological condi- tion, even although it may be very trivial. We can not, indeed, say what the exact condition is, because we find lithates appearing in the urine after violent muscular exertion accompanied by profuse sweat- ing, so that they may possibly represent some of the products of mus- cular waste; but we also find that they occur in large quantities in the urine after slight indiscretions in diet, although no muscular exer- tion has been undergone, and in these cases we can hardly do other- wise than regard them as products of the imperfect assimilation of nitrogenous matters which ought to have been eliminated, not in the form of urates, but of urea. Now, physiological experiments and ob- servations indicate that the liver is the chief if not the only part of the body in which urea is formed. This at least appears to be the case excepting in febrile conditions, in which, possibly, the urea may also be formed, to a considerable extent, in the muscles. The old notion, then, which connected the appearance of lithates in the urine with disordered function of the liver, is probably in a great measure correct. There is little or no reason to believe that these lithates are formed in the kidneys. They are, probably, simply separated by them from the blood, and their presence in the urine would therefore indi- cate their presence in the blood and tissues. Now, lithates in them- selves do not appear to have any particularly injurious effects, either upon the nervous tissues or the muscles, but, as their presence indi- cates deficient assimilation, they may be accompanied by other sub- stances which have a much more pernicious action, just as there are many bad smells which, /)er se, though very disagreeable, have no marked poisonous action, while other very poisonous substances have comparatively little odor.* Yet the disagreeable odors which accom- pany sewer-gas, although perhaps not always dependent upon its poisonous constituents, warn us of the presence of gases which may be intensely poisonous. Nevertheless, just as the poisonous gases may be present without any disagreeable smell,, so we may have substances circulating in the blood which have the most injurious effect upon the nerve-centers, without the presence of urates in the urine.
The importance of the functions of the liver in reference to assimi- lation is now generally recognized, although for a long time this, the largest gland in the body, was considered to have no other office than simply to secrete bile. Although the bile is useful in digestion it is not of primary importance in this process; but its proper secretion is prob- ably associated very closely with the assimilative functions of the liver, and if the biliary secretion does not take place properly we can hardly expect the assimilation to be perfect.
The greatest care appears to have been taken in the construction of the liver to prevent the bile from coming in contact with the blood, the ultimate radicals of the bile-ducts or biliary capillaries being placed as far from the blood capillaries as the structure of the liver will allow. Notwithstanding this care, the distance between the blood and the bile capillaries is small, though it is sufficient, under ordinary circumstances, to prevent the absorption of bile into the blood. But whenever an ob- struction takes place to the exit of bile, and the presence of bile in the biliary capillaries increases, an absorption of this secretion occurs. Bile is secreted under very low pressure, and a very slight increase in this is sufficient to cause reabsorption. Such an increase as would not materi- ally affect the secretion of other glands, such as the salivary gland, is sufficient to prevent the exit of bile through the biliary ducts, and cause its reabsorption into the blood. The excretion of bile is greatly aided by the pressure which is exerted upon it by the movements of the dia- phragm during respiration, and indeed so low is the pressure under which the bile is secreted that, but for the assistance given by the re- spiratory movement, it would just barely find its way into the duode- num. Although we are accustomed to say " as bitter as gall," accord- ing to my own observations fresh human bile is not bitter. When it is thrown up in consequence of indigestion it is intensely bitter. On one occasion, when making experiments with digitalis, I had taken in the course of two days one grain of the pure alkaloid, and brought on symp- toms of poisoning, with intense vomiting. During this I brought up a quantity of bile of a golden-yellow color, and without the least trace of bitterness. This circumstance struck me as being so peculiar that in my published results I hesitated to call it bile, although I did not
- Brunton and Power, "St. Bartholomew's Hospital Reports," 19,11, p. 283. see what else it could be. But when it remains long in the gall-bladder it undergoes changes, and in some cases of vomiting that I have seen the vomited matters have been of a bright grass-green color. When examined, also, after death, the bile in the gall-bladder is not unfrequently found of a dark color, and the same is probably the case when it is retained in the gall-bladder for any length of time during life. How the Greeks arrived at the notion of giving the name "melancholy," i. e., black bile, to depression of spirits, we do not quite know, but certain it is that depression of spirits is very often associated with indigestion, and, moreover, that the form of indigestion with which we find depression of spirits associated is not so much gastric as intestinal, or, more probably, hepatic. According to Herbert Spencer, we require rapid evolution of nervous energy in order to have exhilaration of the spirits, and depression of nervous energy is associated with melancholy. Now, the effect of bile-acids circulating in the blood, as shown by physiological experiments, is to depress the reflex function of the spinal cord, the functions of the brain also, producing drowsiness ending in coma, and also weakening the circulation by paralyzing the cardiac ganglia. Such a combination of actions is just the one required by Mr. Spencer's hypothesis to produce melancholia, and here we find ancient notions joining hands with modern science.—Practitioner.
- Brunton "On Digitalis," p. 67.
- Vide Wickham Legge, "Bile, Jaundice, and Bilious Diseases," pp. 207, 216, 217.