must produce profound modifications in the nervous tissue of the organ of thought."

In the early stage of insanity the pulse occasionally indicates great activity of the centre of circulation, but more generally the action of the heart is feeble, and the state of the pulse establishes the presence of great vascular, vital, and nervous depression. This condition of the radial artery is quite compatible with a considerable amount of acute mental agitation and muscular violence.

There is considerable difference in the action of the radial, carotid, and temporal vessels, as well as in the intensity of the pulsation of the ascending and descending aorta. Jacobi has called particular attention to this phenomenon, but the consideration of this important and interesting physiological and pathological subject must be deferred for another occasion.

RESPIRATION AND GENERATION.-There are no special morbid conditions of the respiratory function which can be considered symptomatic of incipient insanity, or as indicative of the commencement of organic disease of the brain. The lungs are, no doubt, in close organic sympathy with the brain, and in many cases of mental alienation, the two organs in a marked manner reciprocally influence each other.

The autopsies of the insane often reveal extensive disorganizations of the substance as well as investing membrane of the lungs, which have seriously complicated the psychical disorder, and interfered with the satisfactory progress of the case.

The generative functions in some forms of cerebral disorder are exalted. In other states of the brain and nervous system, they are perverted, impaired, or altogether paralysed. I have known insanity, of a senile type, develope itself by a sudden and unnatural manifestation of virile inclination and capacity, at a period of

life when this function is generally considered to be in a state of dormancy. But this important subject, in all its numerous ramifications, physiological, pathological, and psychological, will be analysed in extenso, when I proceed to consider, in the succeeding volume, the obscure diseases of the cerebrum, but particularly the cerebellum, as influencing, directly and indirectly, the reproductive organs.

CHAPTER XXV.

General Principles of Cerebral Pathology, Diagnosis, Treatment, and Prophylaxis.

PATHOLOGY. It was never my intention to enter, in this work, at any length into a consideration of the subject of cerebral and mental pathology. This vast and important field of scientific research must, as far as this treatise is concerned, be but cursorily examined, if not left altogether unexplored. This is unavoidable, considering the number of complex and disputed questions involved in its investigation.

The obscurity that envelopes the pathology of the brain is admitted by every writer whose attention has been directed to its analysis. How vain and illusory would it be were I to attempt to embody in a few pages anything approximating to an accurate conception of the numerous changes, functional and organic, which the brain, appendages, and vessels are susceptible of, and which are known to give rise to a variety of types of cerebral disease and mental disorder?

Let me briefly illustrate the difficulties of the subject. A gentleman, aged fifty-six, apparently in good health, and with, it is alleged, no constitutional predisposition to disease of the brain, was the subject of a violent mental shock. I purposely avoid going more into detail. Insanity, in its most acute form, developed itself. The mental excitement was of a most frightful and alarming

character. There was nothing in the state of the pulse, condition of the carotids or temporal arteries, or in the action of the heart itself, to justify the conclusion that there was any great disturbance of the vascular system. The head was cool, the conjunctivæ presented a normal appearance, and the tongue was but slightly furred. A most careful examination was made with the view of discovering the existence of physical complications, but none were detected. His delusions consisted in a belief that he was surrounded by evil spirits, and that some of them were engaged in tearing him to pieces. He was treated by means of prolonged hot-baths, cathartics, and sedatives, but no persistent impression was made upon the malady. The evident vital depression that characterized the attack clearly contra-indicated antiphlogistic remedies; in fact, so great was the debility, that wine and ammonia to a considerable extent were administered, with the view of sustaining life during the fearful paroxysms of maniacal excitement which so remarkably distinguished the mental disorder. He died, and a few hours afterwards a most careful post mortem examination was made. To the astonishment of every one who was present, no disease was discovered in the brain. The cerebral substance was of normal consistence, the membranes enveloping the brain exhibited no structural change, and the numerous vessels ramifying through the organ were free from disease as well as congestion. In general terms, the brain appeared to be in a healthy condition. The heart was unusually small and flabby; the liver, stomach, and bowels presented no symptom of disease. In one of the kidneys there was evidence of the commencement of granular disease. We had no reason to suspect the presence of urea in the blood or in the substance of the brain, and therefore no analysis was made with a view to its detection.

A gentleman holding an official position in one of our colonial dependencies, came to England on sick leave. Whilst in this country he formed an unhappy attachment to a lady whom he afterwards found to be a married woman living separately from her husband. This discovery caused at the time considerable agitation, eventually resulting in great mental depression. This state of mind. continued for four or five weeks, during which period it was necessary to have him watched with great care, with the view of preventing him from committing suicide. At the expiration of three months from the commencement of his illness, the character of the affliction entirely altered. He became violently and acutely excited; he required three attendants to be constantly with him, and these he frequently attacked with great furor, threatening to murder them. This condition of cerebral and mental exaltation was associated with great vital depression. The case bid defiance to all treatment. None of the usual remedies appeared to touch the malady. There was no particular variation in the symptoms up to the period of death. At the post mortem examination the brain was carefully examined. It was in a perfectly bloodless, or anæmic condition. I never saw a brain so pale and free from blood. No disease of importance was discovered in any other part of the body.

A gentleman, alleged to have been previously free from all symptoms of mental derangement, became much impressed on hearing an exciting sermon. Great mental excitement soon followed, ending in a furious attack of mania. There was no symptom in connexion with the case to justify the conclusion that there was activity of the circulation. The pulse was weak, and the action of the heart feeble. The case appeared in its principal

features to resemble those previously detailed. After death I examined the brain in conjunction with Dr.