The effect upon the insane of diminishing the momentum of blood towards the brain, is another proof how much the afflux of that fluid influences the operations of the intellectual faculties.

Parry's experiments, by compressing the carotid arteries in various cerebral disorders, and of suspending the paroxysms of mania so long as the pressure was continued, tend to prove this fact.*

John Bell discredited the effect of these experiments, and suspected Parry to have been mistaken in his belief that he had stopped the circulation through the carotids,

man swooned; but on reviving, he was the same as before. Next morning he was more tranquil. Two days afterwards, three ounces of blood were abstracted and a pound was transfused. During the operation, he described a sense of heat along the arm, and passing under the axilla. The pulse rose. A plentiful sweat on the face followed. At this instant the pulse varied, and he complained of pain in the kidneys, was sick, and felt as if he would choke. When the blood was stopped, he vomited up the meat he had previously eaten, and felt an urging to urine. After straining and vomiting for two hours, he fell asleep, and slept ten hours. He awoke calm, and in possession of his mental faculties; but complaining of pain in his limbs, and lassitude. The urine he voided was as black as soot. He continued sensible, but sleepy all that day. On the following, his urine was of the same colour, and he bled freely from the nose. The succeeding day he was still sensible, and his urine began to resume its natural appearance."-Philos. Trans. vol. ii. p. 617.

The syncope and variation of the pulse, the increased heat and succeeding sweat, the determination of the received blood to the kidneys, and the sympathetic affection of the stomach, the consequent repose of which he had been so long bereft, and, lastly, the restoration of the mental faculties,-all follow the experiment in the order our physiological knowledge and inferences would lead us to expect.

Although there is no exact description of the symptoms of the maniac's case, except want of sleep, yet it demonstrates the direct influence of the sanguiferous system on the intellectual faculties, and raises the presumption that some error in the circulating medium was, in this instance, the proximate cause of the insanity.-B.

* Lond. Med. Mem. vol. iii.

by the pressure he applied.* The good effects of tying the carotid artery on the side in pain, in the ordinary headach, attended with throbbing of the carotids, has since been shewn by Sir Astley Cooper and Mr. Travers, and the results in some degree confirm those of Parry.+

However this may be, a marked and very visible pulsation of the carotids is not an infrequent precursory symptom of mania, and even of melancholia. It sometimes may be observed in other cases. In a cataleptic maniacal female, whose case I shall hereafter detail, previously to the cataleptic symptoms arriving at their acmé, the pulsation of the carotids was always strong, and discernible by the eye.

In some recent cases of mania, attended by severe headach, and evident determination of blood to the head, while pressure was continued on the carotids, I have found there has been a partial, though not a complete suspension of the symptoms. In one young woman, liable to sudden and furious maniacal paroxysms, if the coming on of the premonitory pulsation of the carotids were watched, and pressure by the thumb was applied, the paroxysm was either prevented or moderated.

Very delicate young females are more subject to cephalic pains than the more robust and plethoric, often arising from excessive determination to the head. But from their appearance, such a cause being unsuspected, a stimulating plan of treatment is often adopted; and hence insanity is a frequent consequence. In these subjects, however, I have observed the vascular system to be very fully developed, generally accompanied by much nervous irritability.

Many diseases induce conditions in us opposite to those upon which themselves depend, and often thus effect their own cure.

* Principles of Surgery, vol. ii.

P. 256. + Medico-Chir. Trans.

Sydenham mentions a species of mania supervening to an endemic intermittent which prevailed. This, à priori, might seem to militate against the conclusion, that insanity is generally consequent to an over-excitement of the vascular system. But experience shews there is nothing in this fact inconsistent with the course of these disorders. High inflammatory affections, such as pleurisy, &c. are well known to succeed those intermittents of paludal soils which produce the most marked effects of debility; and, vice versa, intermittents sometimes supervene in a day or two on the removal of pleurisy.* The former occurrence was so common in Zealand, that it is noticed by Drs. Blane, Borland, and Lampreire, in their report to the British Government on the sickness of our troops in that country, in October -1809.

Hence we may suppose, that after sustaining a severe ague, which always leaves a great degree of debility, a re-action consequently follows, totally subversive of that equilibrium in the balance of the circulation which constitutes a state of health; and this inordinate action may either produce actual inflammation and delirium, or delirium without inflammation, or, in other words, insanity.

The phenomena of fever and those of insanity differ in every thing but the mystery in which their causes are involved. Still, they are both morbid actions of the system, and illustrate the physiological axiom, that nature will not suffer two morbid actions to proceed together. Thus, the appearance of a disease, when another is already in progress, will suspend the original disease, which will again resume its course when the intruder has finished his. An attack of mania will suspend asthma in several cases of pulmonary consump

*Trans. Soc. for Improving Med. and Chir. Know. vol. iii. p. 538.

tion, when the patient was in the last stage of exhaustion and debility, and life fast ebbing, I have witnessed an access of mania restore the patient to instant strength, all former symptoms being suspended; but when, after months' continuance, insanity has ceased, the pulmonary symptoms have re-appeared, and death immediately closed the scene.

The effect of a new morbid action in superseding another already existing, is in no instance more forcibly exemplified than when fever, spontaneous or artificial, supervenes on insanity. Nor, perhaps, can stronger proofbe adduced of the effect of the circulation on the intellectual faculties.

Fever is a very common termination of a maniacal attack; and it will have this effect in cases where the condition of the circulation materially differs. In some insane persons, the impetus of blood to the brain appears to be constant; in some, it is occasional only; in others, it is deficient, and the brain receives too little blood.

If an access of pyrexia do not effect a permanent cure, yet sometimes, so long as this new action continues, the understanding has been perfect, or much improved.

The essence of fever is probably increased action in the vascular system, however that may have originated, When, therefore, an attack of fever removes insanity in any of the three conditions of the circulation referred to, we may infer, that in the first it relieves, by the new morbid action being more powerful than the existing one, and thereby superseding it; in the second, by equalising the deranged balance of the circulation; in the third, by imparting such a degree of momentum to the arterial impulse that sufficient blood is carried to the brain to restore its deteriorated energies.

The most powerful remedies prescribed for the cure of insanity act by inducing artificial fever, i. e. by creating such an excitement in the system as increases the

impetus of the circulation: of these, exercise, the bath, mercury, antimony, and tonics, are examples.

The first effect of accelerated circulation is to increase the activity of the brain. This is often remarked on the accession of simple fever, as well as of incipient inflammation of certain parts of the encephalon. As sensation is more acute, the imagination becomes more vivid, and deprivation of sleep follows; and if the patient sinks into a momentary slumber, frightful images present themselves, and exhibit all the phenomena of delirium.

An attack of typhus has, while it continued, restored reason, and even recollection, in cases of long-continued insanity; though, upon the subsidence of the fever, insanity has again recurred.

Mr. Tuke mentions a case of a woman who had been fatuous for years, and who, being attacked with typhus fever, recovered a perfect recollection of persons and events; and who, upon the subsidence of the fever, was precisely in her former state of mental alienation.* Other authors refer to similar effects, though their histories of the cases of insanity are rarely sufficiently exact.

Recovery of reason from the intervention of fever is so common, that I shall quote only one instance in my own practice.

A gentleman, aged forty-five, in a state of melancholia, with a strong propensity to suicide, was walking with his keeper on Battersea Bridge. By a sudden effort he broke away, and jumped over into the Thames. It was on a Sunday, and as many boats were passing on the river, assistance was immediately given; but he resisted so much, that it was only by main force he was taken out of the water and conveyed to his residence.

Having some distance to go in his wet clothes, he caught a violent cold, followed by rigors and a smart

* Description of York Retreat, p. 137, in notâ.