296. From the intimate sympathy which subsists between the nerves of the stomach and the brain, it is not extraordinary that any casual derangement of the digestive process should communicate its influence to the head. Dr. Warren1 has described this complaint with an accuracy which, as far as description goes, leaves nothing to be desired. He states that there are two forms of dyspeptic headach; the one he refers to a fault in the stomach, the other to a defective action of the upper bowels. The former is distinguished by a languid and feeble, but not an unnaturally frequent pulse; the tongue is whitish and slightly coated; the edges are of a pale red colour. The patient perceives a sensation of mistiness before the eyes, and general indistinctness of vision; he feels a dull pain or weight in the head, attended with some confusion, is slightly giddy, and fearful of falling. These symptoms are attended with slight nausea, or an uneasiness and sense of irritation in the stomach; and often also by a feeling of constriction about the fauces, accompanied with a watery secretion from the posterior part of the mouth.

1 Medical Transactions, vol. iv. p. 333.

Coldness, slight stiffness or numbness of the fingers, are sometimes present: and the other parts of the system are, in general, affected with a great degree of nervous sensibility. The second species of headach, or that depending upon irritation in the bowels, probably in the duodenum, is remarkable for the appearance of brilliant ocular spectra1 which distress the patient; there is chillness of the body, and coldness and dampness of the hands and feet; the pain in the head is very severe, attended with a sensation of coldness and tightness of the scalp, slight giddiness, weight, distension and stiffness of the eye-balls. In some cases, as these symptoms increase, they are accompanied by tingling and numbness of the fingers and hand. The tongue, in this disorder, is usually covered with a yellowish white fur, and is often very considerably coated with it. The pulse is of the natural frequency, but languid; nausea is often present, but seldom in so great a degree as to produce vomiting. There is usually flatulency, and a sensation of dryness and inactivity of the bowels. This last symptom I consider as pathognomonic: the patient feels as if his bowels had lost their sensibility, and were unable to propel their contents, which occasions a peculiar sensation of weight and stoppage.

Dr. Warren observes, that the appearance of the stools vary so much, that a general rule cannot be drawn from them; but he believes, that in all cases of headach of this description, they will be found of an unhealthy quality. The most frequent appearance in them is bile in too large a quantity; sometimes of various colours, and of different degrees of viscidity: occasionally the evacuations have a natural appearance, but contain portions of undigested food. At other times, the stools are of a faint yellow colour, and float upon water, giving out an odour like that of saliva: a very common appearance, especially where there has been great dejection of spirits, is a loose stool, of a dark greenish-brown colour, in smell resembling that of the grounds of sour beer.

1 Depending probably upon what has been termed the Phosphorescence of the Retina, and produced by pressure, as any person may readily observe by pressing the eye-ball outwards with the point of the finger, when a circle of light will be perceived; in like manner in the act of sneezing gleams of light are seen. In the case of dyspeptic headach the effect is probably induced by the pressure of the blood-vessels upon the retina.

297. The stomach headach generally occurs in the earlier stage of digestion; that which may be termed the duodenal headach, takes place when the food has passed into the intestines. The former is relieved by an emetic, the latter receives little or no mitigation from such a remedy: this is consonant with our theory of its origin; whereas, a purgative, as we should expect, generally cuts short the paroxysm, by hastening the expulsion of the offending cause. The practitioner, however, will remember the circumstances that may render the administration of an emetic safer than that of a purgative.

298. From the symptoms above related, he will not be at a loss to discriminate between these two species of headach; but pain in the head may arise from causes distinct from the alimentary canal; as from congestion in the brain, from its internal disorganization, from diseased bones of the skull, or from a deranged state of the nervous system. It will be useful to point out the diagnostic symptoms by which each of these affections may be distinguished. Dr. Warren observes, that headachs which arise from congestion in the brain, are distinguished from those of dyspeptic origin, by the presence of plethoric symptoms, by a full and oppressed pulse, by a difference in the character of the pain, which, in the headach arising from fulness of blood, is accompanied with throbbing, and a sense of action in the system, which alarms the feelings; while the pain of dyspeptic headachs is described as being either a dull aching, or else a racking pain, often moving from one part of the head to another, and attended with soreness of the scalp. In the first, the eyes look red and full; in the second, they have a depressed and languid appearance.

Those which arise from internal disorganization, the same eminent physician considers to be marked by an acute fixed pain, by a quick, irritable, and sometimes irregular pulse; but should pressure on the brain have taken place, the pulse is full and slow, but is not attended with the steady violent heat which accompanies sudden congestion of blood in that organ. When headach is caused by chronic disease of the bones of the skull, it is distinguished by the constancy of the pain, which is confined to one spot, whence violent shootings proceed to some fixed point. As the disorder advances, slight symptoms of pressure on the brain ensue; and on examination, a tenderness of the bono is observed. The nervous headach is distinguished by the absence of constitutional disorder, and by the small-ness of the space on the surface of the head which the pain occupies.

299. There sometimes occurs a soreness of the scalp, with shooting pains, which are produced by the slightest touch. This affection, I believe, generally depends upon some derangements of the biliary system.

300. There is a species of headach which would appear to depend upon a languid circulation through the brain; it occurs after an excess of wine; or, in women, during the catamenial discharge. It is described as rather resembling numbness than pain, or that sensation which is produced by intense cold. The languor of the circulation, pallor of the countenance, and other symptoms of debility, will offer sufficient means for distinguishing it.

301. If the dyspeptic headach be allowed to take its course, it will generally terminate in a few hours; but when it has become habitual, it is often protracted through one, two, or more days. Its cure is to be effected by those means which we have afterwards to consider, as the best modes of rectifying the errors of the digestive organs.

302. Cutaneous eruptions are not unfrequently produced by a fit of indigestion: such affections are popularly denominated surfeits; they are generally of short duration, and disappear on the removal of the offending cause; although severe and inveterate diseases of the skin are sometimes established, and continued, by a chronic disease of the stomach or other digestive organs. The best mode of treating such affections, and the diet which should be employed for their cure, will form a subject for future consideration.