hours. If the patient emerge from the comatose state, convalescence is usually speedy. Of 20 cases observed by Pepper, in 3 insanity followed. This sequel did not occur in over 100 cases received at the New York Hospital. Temporary delirium succeeding the attack is occasionally observed. Paralysis is neither a concomitant nor a sequel.

As already stated, the pathological character of the affection, in all cases of insolation, is not uniform. Cases of sudden death from exhaustion or syncope, produced by heat and over-exertion, are reckoned among cases in which the morbid condition is quite different. A certain proportion of cases are truly apoplectic; the appearances after death, the character of the attack, and all the symptoms denote apoplexy. In other cases, which, probably, constitute the majority, the pathological character is mixed; an apoplectic condition is combined with exhaustion. It is highly important to take cognizance of these differences as regards pathological character, in treating the different cases which are grouped together under the name insolation.

Excessive heat is the important causative agency, but other circumstances co-operate in the causation. Muscular exertion, unduly great or prolonged, is a powerful auxiliary cause. Persons are generally attacked when engaged in labor, but there are exceptions to this rule. Dr. Swift states that, of the cases which he observed, a large proportion were attacked shortly after dinner. The concentration of innervation upon the processes of digestion, the distension of the stomach with food and liquids, the latter being frequently taken in large quantity, and perhaps, in some cases, the disengage ment of gas from chemical changes in the ingesta arising from indigestion, will account for the fact stated by Swift. In most cases, persons are attacked when exposed to the direct rays of the sun, but there are exceptions to this rule. Swift states that eleven patients were attacked on the same morning in the laundry of one of the large hotels in this city, and several cases were brought to the hospital from a sugar refinery. Soldiers are not infrequently attacked after they have retired to their tents.

Cases are more frequent by far in tropical than in cold or temperate latitudes, and, in the latter, they occur during the heated term of summer when the weather is unusually and continuously hot. Atmospheric influences other than heat have been supposed to be involved in the causation, viz., an unusual accumulation of electricity, dryness and rarefaction of the air; bat facts showing the importance of these influences are wanting. The number of cases in the same place in different years varies greatly. Prof. Dickson states that in Charleston, S. C., more persons died from sunstroke in 1824 than in any twelve other years; and in the city of New York in the summer of 1853 there were 260 cases reported, whereas in no previous year had there been more than 36 cases.1

The attack generally takes place at periods when the heat of the day is at its maximum. Of the 60 cases observed by Swift, 40 occurred between 11 A. M. and 4 P. M., 17 between 4 and 9 P. M., and 3 between 8 and 11 A. M.

Feebleness from disease or other causes renders persons more liable to an attack.

The diagnosis is, in general, made without difficulty. The circumstances connected with the attack and the symptomatic phenomena are sufficiently distinctive. Apoplexy with extravasation of blood is to be distinguished by the existence of hemiplegia. Persons deeply intoxicated are not infrequently brought into hospitals as cases of sunstroke, but the characters of alcoholic coma suffice for its discrimination.

Exclusive of mild cases in which there is transient stupor or insensibility,

1 Elements of Medicine, 2d edition, 1859.

the danger in cases of insolation is always very great. The death-rate ranges from forty to fifty per cent. If, with deep coma, the breathing be stertorous, sighing, or moaning, the prognosis is extremely unfavorable. Great frequency and feebleness of the pulse, relaxation of the sphincters, tracheal rales, and complete immobility are forerunners of a fatal termination. Convulsions are extremely unfavorable. Of the cases observed by Swift, none recovered in which the pupils were contracted. In accordance with the difference in pathological character in different cases, the mode of dying is sometimes by rapid asthenia or syncope. This mode of dying is exemplified among the cases in which the death is notably sudden, taking place in the space of a few moments after the attack. The mode of dying in other cases is by apnoea, but, in the larger proportion of cases, by apnoea and asthenia combined.

The treatment is to be adapted to the pathological character of the affection, as represented by the symptoms, in individual cases. Pursuing this course, therapeutical measures, so far from being the same, will be diametrically opposite in different cases. In cases of nervous exhaustion, the danger being of death by rapid asthenia or syncope, complete rest is of the first importance. The removal of patients to their homes or to hospitals, in this condition, may contribute in no small measure to a fatal result. Stimulants are to be administered by the mouth very cautiously in order to avoid exciting vomiting. They may be given with less risk by the rectum. Alcoholic stimulants may be administered by enema. The spirits of turpentine given in this way are recommended. All restraints of dress are to be removed. The patient should be kept in as cool and pure an atmosphere as possible. If the surface be hot and dry, sponging the body with spirit and water should be employed. These should constitute all the measures employed during the attack. Cathartics, emetics, bloodletting, and all depressing agencies are pernicious. The symptoms representing the condition which calls for the treatment as just stated are frequency and feebleness of the pulse, weakness of the heart-sounds, with absence of stertor and the embarrassment of breathing indicative of cerebral compression.

In well-marked apoplectic cases I believe bloodletting to be the measure especially indicated. The treatment called for is the same as in congestive apoplexy, which, in fact, in these cases, the affection is. The life of the patient may depend on the prompt employment of bloodletting. The bowels should be freely opened with croton oil. Cold should be applied to the head, either by means of the ice-cap or the douche. The head should be elevated, and everything constricting the chest or neck removed. Revulsive applications should be made to the extremities. The symptoms representing the condition calling for these measures are fulness or hardness of the pulse, slowness of the respiration, and perhaps stertor, heat of the surface, congestion of the face, throbbing of the carotids and temporal arteries.

The question as to the propriety of bloodletting in cases of insolation hast given rise to much discussion and difference of opinion. The doctrine which I would inculcate is, that to abstract blood is vastly important in some and destructive in other cases. Never to employ bloodletting, and to employ it in all cases, would be alike injudicious. It is, of course, for the judgment of the practitioner to discriminate between the cases in which bloodletting is called for and the cases in which it will do harm. I have noted several cases which apparently exemplify the importance of bloodletting; and I am led to introduce a brief notice of these cases in view of the fact that, at the present time, some and perhaps most practitioners consider this measure improper in all cases of insolation.

On the 9th of August, 1862, eight cases of coma from sunstroke were admitted into Bellevue Hospital. Of these cases, 7 proved fatal. Bloodletting

was employed in only one case, and in this case the patient recovered. This was the last case admitted on that day, and bloodletting was resorted to in that case by the house-physician, Dr. Martin, mainly in view of the fatal termination of the seven cases under other measures of treatment. In the case which recovered the coma was as profound and the symptoms, in general, apparently as unfavorable as in the other cases. The breathing was stertorous, the pupils contracted, the skin hot and dry, and the pulse frequent, but full. Sixteen ounces of blood were taken from the arm, and the temples freely leeched. The patient came under my observation on the following day. He was then quite comfortable, and complained only of debility. He recovered his strength rapidly, and was discharged in a few days, well. He gave the following account of his attack: He was at work in the sun at Central Park. The night previous to the day of the attack he had suffered from headache, which continued up to the time of the attack. For some time before the attack, he felt so extremely weak as scarcely to be able to work. He suffered from the heat, and the headache was severe. He did not perspire. At length he felt unable to work longer, and started to go home. He walked a certain distance, and, from a sense of weakness, sat down. From that time to midnight in the hospital he recollected nothing. He was found in a state of insensibility and brought to the hospital, distant about two miles from the Park.

On the 3d of August, 1863, the hottest day of the season up to that date, several cases of sunstroke were received into Bellevue Hospital. I have not noted the number. Of these, one case recovered under free wet-cupping, ice to the head and spine, and purging with croton oil. In this case convulsions occurred whenever the body was moved. The skin was hot, and the pulse frequent and vibratory. The treatment in the other cases is not noted.

On the 13th of August, 1864, a patient was admitted into one of my wards at Bellevue Hospital, who had been found in a state of insensibility in the street. The pulse was 100 per minute, and had considerable force; the breathing was stertorous, the skin hot, the pupils neither contracted nor dilated, but not responding to light. Eighteen ounces of blood were taken from the arm, and the cold douche applied to the head. These measures constituted the treatment. He recovered his consciousness in an hour and a half after the bleeding. On the following day he reported himself to be quite comfortable, and was discharged in the afternoon of that day.

In the majority of the cases of insolation, symptoms denoting congestive apoplexy are combined, in variable proportions, with those denoting exhaus tion. The importance of bloodletting in these cases is to be measured by the predominance of the apoplectic phenomena, and it is contraindicated if the predominance of exhaustion be denoted by great frequency or feebleness of the pulse. The success of the treatment will depend on the judgment of the practitioner in deciding whether bloodletting be called for, or otherwise, and, if indicated, in determining the amount of blood to be taken. Discrimination is also important in prescribing the croton oil. If the danger be from exhaustion, an active purgative is not indicated. Cold to the head is important in proportion as the symptoms of cerebral congestion predominate. On the other hand, in the cases in which the circulation is notably feeble, stimulant remedies by the mouth or rectum are called for. In all cases quietude is important. In the cases in which convulsions occur, these may be excited by movements of the body.

There is reason to believe that, under judicious management, many cases of insolation which terminate fatally would have ended in recovery, were it not for the necessity of transporting the patients to their homes or to hospitals, and delay in obtaining medical aid.

CHAPTER II.

Acute, Cerebral Meningitis-Anatomical Characters-Clinical History-Pathological Character-Causation-Diagnosis-Prognosis-Treatment-Chronic Meningitis-Tuberculous Meningitis Spinal Meningitis-Cerebro-Spinal Meningitis-Anatomical Characters-Clinical History-Pathological Character-Causation-Diagnosis-Prognosis-Treatment-Hydrocephalus Hydrorachis.

INFLAMMATION within the cranium may be seated, primarily, either in the membranes investing the brain or in the cerebral substance. As regards the membranes, the dura mater is rarely, if ever, the primary seat of an inflammation. When this membrane becomes inflamed, the inflammation follows either an injury of the skull, disease of the bones, or a morbid growth springing from the membrane, and the inflammation is circumscribed. Inflammation of the meninges is generally seated in the arachnoid and pia mater, and the term meningitis is applied to inflammation of these membranes. The relations of the arachnoid and pia mater are such, that one can hardly be inflamed to the exclusion of the other; and pathologists have differed as to which one of the two membranes is primarily or chiefly affected. It is not practically important to settle this question. The terms arachnitis and pieitis would be appropriate to denote an inflammation of the arachnoid and pia mater separately, but in view of the difficulty of determining in which the inflammation has its point of departure, the term meningitis is to be preferred. Inflammation of the meninges of the brain should be called cerebral meningitis, in order to distinguish it from inflammation of the meninges of the spinal cord, or of the brain and cord. Inflammation of the meninges of the cord is spinal meningitis, and of both the brain and cord, cerebro-spinal meningitis. Inflammation originating in the substance of the brain may be distinguished as cerebritis. Cerebral meningitis may be acute, or it may exist as a subacute and chronic affection. These two forms will claim separate consideration. A form of inflammation known as tuberculous meningitis will also be considered under a distinct head. In this chapter, the three forms of cerebral meningitis just named will be first considered; afterward spinal meningitis and cerebro-spinal meningitis, with a brief notice of hydrocephalus and hydrorachis.

ACUTE, CEREBRAL MENINGIT IS.

Were the importance of a disease to be measured solely by its frequency, this would deserve but little attention. It is extremely rare, especially after adult age. But its gravity commends it to the consideration of the student and practitioner.

ANATOMICAL CHARACTERS.-The appreciable local results of acute inflammation in this situation are those of serous inflammations, viz., more or less redness from vascular injection and the presence of serum, lymph, and pus. These inflammatory products, however, are, for the most part, beneath, not upon, the arachnoid membrane, that is, in the meshes of the pia mater. The

redness proceeds from the injection of the vessels of the pia mater, not from the presence of red globules in the arachnoid. Lymph, in more or less abundance, is spread over the surface of the brain under the arachnoid. It is observed especially in the sulci between the convolutions, at the superior and lateral portions of the cerebrum, being less abundant or absent at the base of the brain. The presence of pus is denoted by a greenish color. A small quantity of exudation may be scraped from the outer surface of the visceral arachnoid, and, exceptionably, it is more or less abundant here, as well as beneath this membrane. The outer surface of this membrane is sometimes abnormally dry. There is more or less effusion of turbid serum in the arachnoid space, rendering the arachnoid membrane opaque. The membrane is more easily detached than in a healthy condition. The ventricles generally contain a small or moderate quantity of turbid serum.

It is to be borne in mind, in examinations after death, that the presence of serum in considerably larger quantity than is usually found beneath the arachnoid membrane is not adequate proof of meningitis. This occurs from atrophy, or wasting of the brain, incident to chronic disease in any part of the body. The criterion of inflammation is lymph in quantity to be appreciable by the naked eye, or pus. Nor is mere opacity of the arachnoid membrane enough. As remarked by Rokitansky, "opacity and thickening of the arachnoid are very common post-mortem appearances; after middle life, a moderate degree of them is almost constantly found, and their absence is the exception." In autopsical examinations, meningitis is apt to be considered as having existed on insufficient grounds.

CLINICAL HISTORY.-Simple acute meningitis may be abrupt or gradual in its development. The premonitions are the symptoms of determination of blood or active congestion, and this, in fact, is the morbid condition. After the development of inflammation, there is a marked variation in symptoms at different periods of the disease, viz., prior to and after the effusion of lymph and serum. The career of the disease is divisible into two stages, the division being based on the occurrence of the products of exudation. The first stage extends to the period when, owing to the pressure of lymph and serum, a marked change in the symptoms occurs.

The first stage has been distinguished as the "stage of excitement." It is characterized by pain, usually very intense, referred to the entire head, sometimes greatest in the anterior and sometimes in the posterior portion. The pain is the same as in cases of active cerebral congestion. Delirium frequently occurs; and the delirium, in this stage, is generally active or maniacal, but in some cases hilarious. Owing to the prominence of the delirium, patients are sometimes carried to insane institutions, the affection being mistaken for functional mania. Convulsions may occur, especially in young subjects. The special senses of sight and hearing are morbidly acute; light and sounds occasion distress and increase the cerebral excitement. The eyebrows are corrugated to shield the eyes from light. The face is flushed. The carotids and temporal arteries pulsate strongly. The head is hot. Vomiting generally occurs in this stage, and is often prominent as a symptom. The bowels are usually constipated. The abdominal walls are depressed. Febrile movement is more or less marked; the pulse is accelerated, strong, and full, and the temperature of the body is raised. Exacerbations occur in which the delirium and cephalalgia are notably increased. The symptoms, in general, are those of active congestion, differ ing only in being more intense and persisting. The duration of this stage

Pathological Anatomy.