394 PATHOLOG Y interchange of its particles, but also by the control of the amount of blood sent to the skin on the one hand (say, in warm weather) and to the muscles and viscera on the other (say, in cold weather). The vaso-motor nervous mechan ism, therefore, is an integral part of the nervous control of the bodily temperature. But there is reason to think that the regulation of the bodily heat is committed to the charge of a still higher and more commanding centre in the nervous system than the vaso-motor. It is a remark able fact, observed from time to time in clinical practice, that certain cases of injury to the brain, from fracture of the skull or internal hiemorrhage, are attended with a quite phenomenal rise of the body-temperature a rise to 107 or 108 Fahr., and that, too, when there is nothing strikingly unusual in the vaso-motor effects, as revealed in the skin or elsewhere. In such cases it is the surface- region of the pons Yarolii, the great cerebellar commissure, that has been injured or compressed by the effusion and coagulation of blood. The evidence of specially-devised experiments confirms and amplifies the clinical evidence ; and it is considered in physiology to be a well-grounded fact that there are thermic or heat -regulating centres in the brain, one, at least, being in the region of the pons Yarolii. Bernard would further assume the existence of " calorific " and " frigorific " nerves side by side with vaso dilator and vaso-constrictor. Thermic Fever and Heat- Stroke. Such, then, being the nicely- balanced and carefully safeguarded mechanism for keeping man s internal heat about 98 Fahr. under all circumstances, the question arises whether we may trace any considerable part of the sickness and mortality of the globe to a marked and conspicuous failure or break-down of this mechanism of adaptation : " But errs not Nature from this gracious end, From burning suns when livid deaths descend?" Thermic Undoubtedly the ardent or thermic fever of Indian practice, the fever. heat-apoplexy, heat-stroke, or sunstroke, is the direct result of an upset or disintegration of the heat-regulating nerve-centre. Either the disorder of innervation is shown in sudden syncope or depres sion of the heart s action, as among labourers working or soldiers marching in the sun ; or the effect of atmospheric heat, direct solar or other, is a universal state of venous engorgement, indicat ing profound vaso-motor paralysis, and ending in death from asphyxia, literally the " livid death " alluded to in the couplet ; or the heat-stroke leads to an attack of thermic or " ardent " fever, coming on perhaps in the night within a few hours of exposure, or after a longer interval, having a prodromal stage of malaise, a rise of the body-heat to as much as 108 or 110 Fahr., embarrassments of the lungs and heart, profound brain -troubles, and probably a fatal termination in general venous engorgement and asphyxia. These various forms of heat-stroke all point to a profound dis organization of the nervous centres by the more or less direct action of solar heat, to cardiac depression in the syncopal form, to more general vaso-motor paralysis in the asphyxial form, and to dis organization of the thermic nerve-mechanism in the hyperpyrexial form. When recovery takes place, as it does in a large proportion of cases, there are often lasting traces of injury to the nervous system in other functions than the vaso-motor or thermogenic. These cases of heat-stroke or thermic fever are the most obvious illustrations of a break-down of the heat-regulating mechanism, but they are by no means the most usual illustrations of it. It is in a vastly more common form of sickness, in malarial fevers of all kinds, that we discover the typical failure of the heat-regulating centre under circumstances that tax the self-adapting powers of the body. The enormous prevalence of malarial or climatic fever may be said to be the greatest indication of failure or imperfection . in the adaptation of man to his surroundings. In some few spots, which even the instinct of the brutes leads them to desert for a season, the effects of heat and moisture are such as to induce an endemic diseased habit of body, so universal in its incidence and so insidious in its development as practically to amount to an ethnological distinction (see Heber s description of villagers in the Terai, Indian Journal, vol. i. p. 251). Throughout the whole intertropical zone, and for 5 beyond it in the southern hemisphere and 20 beyond it in the northern, the climatic fever, in its various forms, stands for almost as much sickness and mortality as all other diseases put together. So stupendous a power has it always been that its pathology has with difficulty emerged from the stage of gross materialism and superstition. But malarial or climatic fever is the true "essential" or "primary" fever of the older writers; its paroxysm is the abstract fever of pathological treatises, which is discussed without reference to communicability from person to person ; and, if it has a periodicity which seems to give it specific characters of its own, a little analysis serves to show that its periods of waxing and waning are no other than the cosmical periods of the earth itself. Cullcris Theory of Fever. According to Cullen s theory of fever Primai (which was a modification of Hoffmann s), "the first incident in or the chain of sequences constituting fever is a depressed state of essenti i the brain and nervous system ; spasm of the extreme capillaries fever. results from this depression ; and reaction of the circulation, with its accompanying phenomena, is an effort of the system to overcome the spasm. The Cullenian theory, in a modified form, continues still to be the prevailing creed of those who adhere to the tenets of solidism, and who believe at the same time in the existence of primary or essential fever." This is the language of Christison in 1840 (Tweedie s Library of Mcdicim; vol. i. p. 116) ; and he adds that the chief rival to this doctrine is one which "denies the existence of any primary or essential fevers, and holds them all to be merely symptomatic of somo local disorder." Cullen did not ignore the differences among fevers in respect of the local condition, exanthematous or other ; but his desire for a broad generalization led him to find something common in the antecedents of them all. This was "diminished energy of the brain," and the nervous depression was caused by "human and marsh effluvia." When the disentanglements of the century following are credited to Cullen s doctrine the latter will be seen to be still radically sound. The collocation of " human and marsh effluvia" is nothing but a verbal one ; there is no uni formity of effect among human "effluvia" themselves, but rather specific differences ; in marsh effluvia nothing has ever been found but common watery vapour ; and the characteristic effects of " marsh effluvia " are by no means rare on barren uplands where there is no standing water or decaying vegetation for miles around. The modern disentanglement has put into a class by themselves all the communicable infective diseases which bring more or less of febrile disturbance, and has fixed the attention on the specific features and evolutional antecedents of each. Hence the existence of "primary or essential fever" has come to be denied, except as the abstract febrile state. But it had been forgotten that, for malarial or climatic fevers, there is no communicability, and no specific virus bred in the body or in the body s discharges ; and to them therefore belongs the heritage of " primary or essential fever." The common aguish intermittent is the source of all the concepts that enter into the doctrine of fever, the initial malaise, the cold fit and the hot fit, the crisis and the defervescence. It is to it that the classical description of a febrile paroxysm applies, in paragraphs 16 to 23 of Cullen s First Lines, just as the fever pathology of Hippocrates and Sydenham applies to it; and the first incident in the chain of sequences, according to Cullen, was an "enfeebled energy of the brain." It will be found that this doc trine of primary or essential fever, understanding climatic or malarial fever therein, is fundamentally in agreement with modern physio logical teaching as to the animal heat and the errors in its regulation. Malarial or Climatic Fevers. Turning, then, to the analysis of a Parox- paroxysm of ague, we find that there is a preceding sense of languor ysm 01 and un fitness for a few hours ; all at once the patient begins to ague, feel cold, he shivers, his teeth chatter, his skin becomes " goose- skin " from the powerful contraction of all the muscular elements in it. If this occurred in the orderly course of regulating the body-heat it would mean that the internal temperature was falling below the mean ; the vigorous contraction of the blood-vessels on the surface of the body is by way of preventing the escape of heat. But the truth is that the body-heat is rising much beyond the normal all the while that the skin is acting so as to keep in the heat. This procedure at cross purposes goes on for a few hours, during which the internal heat may rise to 104 or 105 Fahr. The cold fit passes into the hot, and then the crisis is reached ; there is a violent rebound, the muscular elements of the skin and its vessels relax, perspiration flows freely, the kidneys begin to remove all the products of excessive and uncalled-for combustion, and in the morning the patient awakes with probably no very serious effects after his feverish night. Assuming the case to be a common quartan, the individual goes to his work next day feeling tolerably well ; on the day after he has probably forgotten all about his feverish paroxysm, if it be his first ague ; and it is not until the afternoon of the third day that he is again reminded of it. Let us say tl>at he is returning from work towards the end of an ordinarily active day ; suddenly he has the same uncontrollable feeling of chills, he shivers, and seeks warmth by crouching over the fire or by wrapping himself in warm clothes. The drama of three days before is repeated, he awakes again from a feverish night, the morning urine being again full of brick-red urates ; he now knows that he is the subject of quartan ague, and that another paroxysm is due three days later, which he is fortunately able to prevent or at least to mitigate by taking quinine in the meantime. Whatever may have induced the first paroxysm, the second is a mere imita tion of it, an affair of habit, just as a return of an epileptic con-
