Hence, sunstroke is much more infrequent upon the high table lands of Abyssinia and the dry belt of our Texan prairies than in the low lands of India or upon our own sea-coast. There is abundant clinical evidence to the fact that direct exposure to the sun is by no means necessary to produce an attack.

Certain conditions act as predisposing causes by lessening the power of the system to resist heat, or by weakening the inhibitory heat center so that it is readily exhausted. The chief of these are race, excessive bodily fatigue and intemperance. Males are much more rapidly affected than females, due, not to one sex being more disposed to attack, but because of the habitually greater exposure of males to the heat. A similar reason may be given for the fact that more cases occur among the laboring classes than among the wellto-do.

Both in this country and in India, Europeans suffer far more than do the natives, but no race is absolutely exempt. Even the negro and the Hindoo resident in India are sometimes attacked, but generally under conditions of great physical exhaustion. Unacclimated residents of tropical climes or alien soldiers are most liable to

be attacked. Among occupations predisposing may be named out-door laborers, hod-carriers, roofers, masons, bricklayers, drivers, or workmen in refineries, laundries, glass-blowers, firemen, etc.

It is, characteristically, a land affection, but with the recent development of steam navigation there have been a great many cases occurring among firemen, stokers and coal heavers, on board ocean-going vessels. The increase in the number of cases among these men has been very noticeable within the past ten years.

. Statistics, compiled by Major Charles Smart, of the United States Army, show an aggregate of 1250 cases of heat and sunstroke occurring in the army from 1868 to 1893, with a total of 47 deaths, 42 of which occurred prior to 1881.

Wood says that the earliest victims to excessive heat are those enfeebled by previous disease, overwork, or insufficient rest; those who have been subjected to intense mental anxiety or to long periods of privation; the ill-fed, and particularly those who are scantily supplied with water; the intemperate, unclean and improperly clad; occupants of over-crowded unsanitary apartments; and, generally, those physically below par, especially if they

carry their disabilities into foreign countries.

Phillips' considers that certain meteorologic conditions predispose to sunstroke, and these involve high temperature, relative humidity, wind and climatologic characteristics, as well as the direct rays of the sun. He seems to think that relatively low humidity is as important a factor of causation as high temperature and direct insolation. He claims that the degree of temperature precipitating sunstroke is a function of the particular climate and not fixed or definite for all locations.

Pathology and Morbid Anatomy of Acute Heat Disorders.

There is much speculation in regard to the pathology of the various forms of heat stroke. That which received the most favorable consideration heretofore was that the malady was an auto-intoxication; but this has not yet been susceptible of definite proof. Gieson modifies this theory by limiting the toxic effect to the ganglionic cells of the spinal cord and encephalon, causing corroboration of his theory, the fact that some degenerative change. He cites, in the blood serum of those bled during an attack of sunstroke, if injected into rabbits, even in small quantity, will cause their death within an hour.

Martin' classes sunstroke under three forms the cerebro-spinal, with death by stertor, coma and convulsions; the syncopal or cardiac type, death taking place by arrest of the heart; and the pulmonary form, with dyspnea and asphyxia. He says that the disease is dependent upon retention in the system of toxic products of retrograde metamorphosis.

DeSanti3 looks upon insolation as in all cases characterized by arrest of the heart, but as dependent upon different causes, arising from intoxication by the products of muscular effort, from asphyxia, or from a malarial infection called into activity by fatigue or heat.

Wood gives, among the post-mortem changes, firm contraction of the left ventricle of the heart, with the right heart and the pulmonary arteries engorged with blood, dark and fluid. The whole body suffers from venous congestion, the blood seeming to leave the arteries and collect in the venous trunks. The arterial coats are

often stained red, apparently by the broken down red corpuscles of the blood. The blood suffers similarly to what it does in low fevers. Its coagulability is always impaired, but not always destroyed, and it is even possible that in the very rapid cases it may not even be affected, decidedly. After death it appears as a dark, thin, sometimes grumous fluid, whose reaction is feebly alkaline, sometimes decidedly acid. Beyond this, nothing abnormal was noted in regard to the blood, altho Levick asserts that the blood discs, as seen by him under the microscope, were shrivelled and crenated, and presented a slight tendency to adhere in rouleaux.

In this connection, Professor Stiles' asserts that a mammal cannot long survive a temperature of 115° of the blood in the left side of the heart; and when exposed to a heated medium long enough to produce this temperature, death must ensue. In experiments he tried, all the symptoms of heat stroke were produced, the fatal results being attributable to paralysis of the muscular tissue of animal life by the heat. While the direct effect of a temperature of 115° applied to non-striated living muscle fiber is its rigid contraction; if gradually applied, the most complete relaxation precedes the rigor mortis. The febrile phenomena he attributes to the paralysis of the blood vessels thruout the body; the blood is poured from arteries to the veins; the heart is roused to tumultuous action, hastening the period of its own complete exhaustion or paralysis; the brain is overwhelmed by the torrents of blood in its dilated vessels; and the "stroke" marks the period of vascular paralysis and of the release of the muscular tissue of the vessels from control of the sympathetic

nerves.

Professor Stiles says that excessive heat is undeniably the morbific agent in the condition, and, whether deaths occur during syncope, coma or asphyxiation, it is the consensus of opinion that the apparatus of ännervation is the channel thru which the wital powers are assailed and that the proper place of heat stroke is among the

neuroses.

Heat Exhaustion-Symptomatology. The symptomatology of heat exhaustion is unmistakable, and is sometimes, tho not generally, alarming in its manifestations. The attack may come on slowly, beginning with a feeling of general weakness and re

laxation, or it may be as abrupt as true sunstroke. The severest cases may occur in those who have been in robust health, as well as in the feeble and weak.

In heat exhaustion the mind is usually clear, the pulse rapid and feeble, the surface cool, the voice very weak, muscular strength greatly lessened, and the feeling of exhaustion extreme. The condition may be intensified to the degree of syn

cope.

In the more severe forms the heart does not seem to suffer principally, but there is great collapse, with palsy of the vasomotor system, great fall of the body temperature and marked general nervous symptoms. In these instances delirium is sometimes a feature.

A peculiar feature of so-called heat exhaustion is the usually relaxed condition of the sphincters, sometimes the mere introduction of the thermometer into the rectum provoking watery dejecta. The bowels are generally open in a simple case of heat prostration, in contrast to the constipation, which is a feature of sunstroke.

Treatment of Heat Exhaustion.

This may or may not be a simple exhaustion or syncope dependent upon excessive atmospheric heat, but the treatment presents few features differing from that of ordinary fatigue exhaustion.

The patient should be at once removed to a cool apartment or to the shade, and placed in the recumbent position, with the head lower than the rest of the body. The clothing should be removed with as little disturbance of the sufferer as possible, and a light covering thrown over him. Sometimes this proceeding, with absolute rest for a limited period, will be all that is necessary to complete recovery.

If the pulse is of low tension, and small or thready, give aromatic spirits of ammonia, brandy, digitalis or strychnin, the first-named being of the greatest value for immediate effect, as it is prompt and powerful without being too prolonged in its action. If brandy is given, it should preferably be administered hypodermically, because it will act more certainly and rapidly, owing to the irritability of the stomach so often present in the condition under consideration. Digitalis is probably ( the least valuable of all the agents, owing to its slowness of action and the long continuance of its effects. A combination of

either of the first-named agents with strychnin is to be advocated, not only because of the action of the drug upon the vaso-motor system and the heart, but also because it stimulates all the important functions. If the pulse is very soft and compressible and the skin moist, it is well. to combine strychnin and atropin in doses of 1-20 grain and 1-180 grain. This is especially recommended by Packard.

Packard quotes the temperature taken in the rectum as an indication as to the necessity for applying external heat or cold. When the temperature is subnormal the patient should be placed between thin blankets and have hot water cans or bags placed around him; or better, he should be placed in a bath-tub half filled with warm water, the head being supported and kept cool by the use of an ice cap or cloths wrung out of cold water, and gentle friction being employed over the trunk and extremities.

Sometimes, while the skin is cold and clammy to the touch, the thermometer in the rectum will show a high temperature. In this case it is best to sponge with cool water-from 66 to 70 degrees to which alcohol in the proportion of one part to four has been added.

For the gastric irritability so generally present, little treatment is necessary beyond the moderate administration of either whisky or brandy upon cracked ice. There is no immediate need of giving nourishment, at least not until the system has in some degree recovered tone. The

first food administered should be fluid in form, such as milk or meat broths, and should be given in very small quantities.

Work of any kind, either physical or mental, should be forbidden for several weeks, and whenever possible there should be complete change of climate. Later, a system of general tonics should be given in order to brace the patient against a recurrence of an attack.

Wood chiefly advocates the use of alcoholic stimulants, digitalis, ammonia and atropia subcutaneously in attacks of this nature, and where the temperature is subnormal the use of the hot bath to about 120 degrees, until the temperature in the mouth approaches the normal.

Prognosis of Heat Exhaustion. There is very little fear of a fatal termination in these cases, yet sometimes the system is permanently enfeebled in its power

of resistance to heat, symptoms of syncope appearing under circumstances comparatively comfortable.

Frequently the occurrence of an attack of heat prostration will predispose the sufferers to an attack of sunstroke, and it will always render them unable to continue in close and crowded rooms. In all cases,

after an attack, it is best to exercise extraordinary care in regard to exposure, and to particularly avoid overtaxing the heart or the excretory system.

Thermic Fever, Siriasis, or Sunstroke.

Altho considered to have practically the same etiology as heat exhaustion, the symptomatology, clinical history, treatment and prognosis of true sunstroke differ so widely from the former that it is

impossible to consider the two under any general heading. The literature on the subject is far from full. Yet there has been much inquiry into the etiology, but, with a few notable exceptions, these seem to have been in the line of a seeking after facts to prove a preconceived theory, rather than a dispassionate inquiry for logical deduction.

The majority of cases of sunstroke seem to occur not necessarily upon the hottest days of the year, nor upon the early days of a heated term, but are most frequent after a high atmospheric temperature has existed for a number of days with very little amelioration. Packard thinks that the heat centers are able to preserve the proper balance between heat production and heat dissipation for a certain length of time, but finally lose control over the heat regulating apparatus of the body, possibly only suffering with the rest of the body from the depressing effect of long-continued excess of atmospheric temperature.

He also says that it is possible that the loss of balance in the heat regulating mechanism may be not, so to speak, central, but may depend upon interference with heat loss as a result of diminution of perspiration, due either to exhaustion of the sweat-glands or, what seems more probable, to deficiency in the serosity of the body from long-continued, profuse sweating on preceding days of the heated term.

Symptomatology of Sunstroke. Wood notes as symptoms of sunstroke insensibility, generally preceded by pain in the head, disordered vision, particularly in the color perception, a sense of weight in the epigastrium, and sometimes nausea and vomiting. The patient complains of everything turning of a uniform color, blue and purple being the colors most generally mentioned. The pupils may vary, being sometimes contracted, occasionally dilated, sometimes unequal.

The skin is very hot and dry, altho cases have been recorded when it has been bathed in perspiration. There may, however, have been some confusion here with cases of the simple heat exhaustion type, possibly unusually severe in their manifestations. Occasionally subsultus tendinum is noticed with great restlessness. Occasionally severe headache and vertigo are complained of, and confusion of ideas, with great precordial distress.

Gihon states that the pulse is generally full and bounding and greatly accelerated. In the latter stages of a fatal attack it becomes irregular, intermittent, thready. The tongue is white and flabby and there is generally intense thirst. The bowels are generally constipated, often with so great atony that injections have but little effect. The urine is sometimes suppressed and always scanty and high colored. The breathing is always affected, sometimes rapid, sometimes deep and stertorous. There is generally a suffused appearance of the face, this sometimes being so deep as to give a cyanosed appearance. The most distinctive feature of an attack is the intense burning heat of the skin, the surface temperature ranging as high as 109°.

Wood speaks of the presence of a distinct odor, characterized as "mousey," particularly noticeable in the somewhat rare cases where the sphincters are relaxed, yet entirely distinct from any fecal odor. It is noticeable in the vomited matter, on the skin, and in the breath. This odor was sufficiently distinctive to enable him to recognize a case by the sense of smell alone. He also noted that the conjunctivæ were often injected, and the motor nervous system profoundly affected. Severe cases presented partial spasms and sometimes even violent convulsions. These were at times epileptiform, occurring spontaneously, or they were tetanoid and excited by the slightest irritation. Sometimes

the motor system suffered paralysis, the patient moving neither hand nor foot.

He sums up the symptoms as usually seen to be those of intense fever accom

panied by profound nervous disturbance (as manifested by insensibility with or without delirium and by motor symptoms such as convulsions or paralysis), by arrest of glandular action and by changes in the blood. In this ordinary form of sunstroke death takes place by asphyxia or by a slow consentaneous failure of both respiration and cardiac action. It very rarely occurs in less than a half-hour after the first decided symptoms, and is usually postponed for a much longer time.

Dr. Wood also speaks of a type of sunstroke in which death results almost at once, and probably always by cardiac arrest, which he calls the cardiac variety. It is very rarely met with in civil life, and among soldiers is especially seen during a battle or at other times when great exertion is being made. tion is being made. Soldiers have been known to drop dead in the ranks by the tens, with no other assignable reason than that of sunstroke of this type, altho the phenomenon was particularly noted after a breastwork was stormed or a hill climbed on the double quick.

It seems a logical conclusion to Dr. Wood that even in very many rapidly fatal cases death occurs from a paralysis of the respiratory centers caused by intense heat. Sometimes there is a consentaneous failure of respiration and circulation. After death the body is generally rigid, due to a rapid and complete coagulation of the myosin. The heat continues after death, and hence there is generally rapid appearance of putrefactive changes. He concludes that:

1. Sunstroke is a fever not depending upon blood poisoning, but upon heat-an ephemeral or irritative fever.

2. Excessive rigidity of the heart is due to the coagulation of the myosin. It is a very pathognomonic symptom of sunstroke.

3. In most cases it is a post-mortem phenomenon,occurring directly after death. 4. In the so-called cardiac variety of sunstroke, death is due to an antemortem coagulation of the cardiac myosin and consequent instantaneous arrest of the heart's action.

Gihon, in his able article in the Twentieth Century Practice, speaks of the similarity of certain symptoms of heat stroke with those of apoplexy, and speaks of the general presence of cramp in the body or

limbs, often particularly referred to a region just below the ensiform cartilage.

De Santi speaks of two classes of heat stroke. In the first the sufferer, who has fulfilled his duties particularly well, suddenly becomes silent, unbuttons his clothing, and, if asked, complains of violent headache and oppression; but he continues his work until the moment he becomes pale and falls, with convulsive movements as if in an attack of epilepsy. The teeth are firmly clenched, the insensibility is absolute, the respiration difficult, the pulse small and irregular, and there is often involuntary voiding of the urine. The waxy pallor of his face attracts special attention. Occasionally this form is varied with asphyxial symptoms. In this case the patient moans, drags in all his motions, and becomes paler and paler, while his lips become blue. The jugular and temporal veins swell, the eyes become injected, the respirations shallow and quick, and he finally sinks gently to the ground. He does not entirely lose consciousness, and when he is laid down and relieved of everything that is likely to interfere with respiration he breathes deeply and soon becomes himself again. Sometimes nervous symptoms, comparatively unimportant, supervene. In the second form the patient begins his work dully, but becomes more animated as he progresses. His face is red, and he does not seem to feel fatigue, but complains of extreme thirst. Suddenly, as if struck by a club, he falls face downward in a state of coma. Here the face is generally suffused, tho it has been observed pale. This state is somewhat long in duration-sometimes two daysand may terminate in death without a return of consciousness. Generally by reducing the temperature, by artificial respiration, by flagellation, and especially by the subcutaneous injection of ether, the coma may be overcome in the course of an hour, but it is likely to return.

Treatment of Sunstroke.

In the mild cases of thermic fever Wood favors the use of the cold bath. Guiteras also favored this mode of treatment, and at Key West, where he treated a large number of cases, he wrapped the patient in a dry sheet, lifted him into a tub of water having a temperature between 80° and 85° and then rapidly cooled this water by the means of ice. The time of the immersion

lasted from fifty to fifty-five minutes, it being regulated by the thermometer in the mouth of the patient. The patient was then lifted out upon a blanket, the skin partially dried and the body lightly covered.

Guiteras found great advantage from giving a moderate dose of whisky and a dose of digitalis, 30 minims, about twenty minutes before the bath. He lays stress upon the importance of avoiding currents of air blowing upon the patient, and of giving the bath in a small, warm room.

The result of the bath treatment was invariably a lowering of temperature, a reduction of the rate of pulse and respiration, and a refreshing sleep. After the second bath the course of the temperature seemed permanently influenced for the better. It was never necessary to give more than two baths in the twenty-four hours, but in some cases they had to be used for many days.

Packard advises, in cases of the milder type-that is, when the rectal temperature does not exceed 104°-simple rest in the recumbent position in a cool room, the application of an ice cap to the head, and sponging of the body with cool or cold water. If there is not a speedy fall of the temperature with these methods, however, he says that a cold pack must be used. He calls attention to the importance of bearing in mind the possibility of subsequent greater elevation of temperature, and on that account directs to keep the patient at rest in a cool room for some hours after the reduction of the bodily temperature and until the atmospheric conditions have become less severe. Cessation from work for a period of at least several weeks must be enjoined.

The treatment, when the high temperature of the patient denotes an extraordinary degree of danger, should be more radical. Martin antagonizes asphyxia by subcutaneous injections of from 15 to 30 minims of ether every hour, this with the conjoined use of artificial respiration. If the face is congested, cold affusions should be made to the face and head, and rubefaction of the extremities induced. Subsequently, to prevent the return of the symptoms of asphyxiation and congestion, and to re-establish the function of the emunctories while favoring the elimination of noxious matters, subcutaneous injections of from two to four grains of cocain, with or without ether, are made three or four times in twenty-four hours.