A Treatise on Fever

by Southwood Smith

In the preceding chapters it has been shown what are the real events which take place in fever, the assemblage of which constitutes the disease: it has also been shown in what order these events succeed each other, and upon what conditions of what organs they depend. To assign further the true relation between these events, is to establish the theory of fever in the only philosophical sense of the term theory: and that relation must already have suggested itself to the mind of the attentive reader.

We have seen that the first indications of disease are clearly traceable to the nervous system: that the disorder of the functions of the brain and spinal cord with which the attack always commences, demonstrates that these organs form the primary seats of the malady: that the derangement in the functions of these organs is truly invariable, and is invariably the first morbid condition that is observed to take place: that there never was a case of fever, from the slightest to the most severe, in which these organs were not in a greater or less degree in a disordered state, and in which that disordered state did not precede every other. This affection of the nervous system then, the invariable antecedent of all that follows, is the primary essential event in the morbid series which constitutes fever.

What the real nature of this primary affection of the nervous system is, we are wholly ignorant, and we ought at once to confess our ignorance. We have already entered into some considerations, derived from the difference in the order in which the phenomena of fever and of inflammation succeed each other, to show that these two diseases are not identical.[^[30]] When these phenomena are still more attentively considered, other differences are observable between them, which confirm the opinion that the two diseases are not the same. Not only is derangement in the nervous and the sensorial functions invariably the first in the series of morbid events in fever, while it is not the first in inflammation, but that derangement is always much greater in the former than in the latter, and proceeds in a regular and determinate course, such as has been fully explained in the preceding pages, and to which there is nothing analogous in the progress of inflammation.

To the condition of inflammation a peculiar but an unknown condition of the blood-vessels appears to be indispensable. To the state of fever, no such condition of any part of the vascular system, as far as we have the means of judging, is absolutely indispensable, although it be very commonly coincident. No such condition appears to be present, at least no such condition has yet been ascertained to be present, either in the very mildest or in the severest form of the disease: at the latter extreme of the scale, at least, we might expect to find the most striking and unequivocal indications of the existence and operation of inflammation, were that agent really present; and yet it is precisely here that the ordinary signs of inflammatory action are completely absent.

Moreover, we have no example of instantaneous death by the sudden excitement of inflammation in any organ, or in any number of organs: inflammation is a process: a certain number of events take place in a certain order; and there is always, as far as has been hitherto observed, some interval between these events. A case is recorded in which inflammation of the bowels (acute enteritis) proved fatal, as was supposed, in eight hours from the commencement of the attack; but so rapid was the process, that the intelligent surgeons who witnessed it doubted whether the time when the disease began could have been noted accurately: at all events, it does not accord with the best-established facts relative to the process of inflammation, that it should prove fatal without the lapse of some hours. Fever, on the contrary, does not need as much as a single hour to complete the work of death. It is well known that the poison which, in a certain state of concentration, produces fever with the ordinary period of duration, in a higher state of concentration produces instantaneous death; and that, in certain climates and seasons, it is not uncommon for persons previously in sound and vigorous health, on exposure to that poison, to sicken and to die in a shorter space of time than is requisite, under ordinary circumstances, for the mere formation of the inflammatory process. The state of the system, in the primary attack of fever, and the state of the system in inflammation, do not, therefore, appear to be identical. The truth is, that we do not know what the real state of the system is in either case, but we see that the phenomena of the one differ from those of the other; to conclude, therefore, that the states are the same is not a sound induction. While, then, we are constrained to admit that we know nothing of the nature of the primary affection of the nervous system in fever, the closest consideration of all the phenomena alike constrains us to conclude, that that affection is peculiar and specific.

This peculiar and specific affection appears to be much more analogous to the condition into which the nervous system is brought by the application of certain poisons, than to that which is proper to pure inflammation. The more closely and extensively the subject is investigated, the more clear and satisfactory the evidence becomes, that the great primary cause of fever is a poison, the operation of which, like that of some other poisons, the nature of which is better understood, and the action of which has been more completely examined, is ascertained to be upon the nervous system. How these poisons act upon the nervous system we do not know, nor can we possibly know, as long as we remain so profoundly ignorant of the nature of the action of the nervous system in the state of health.

It may be considered then as established, that the primary morbid condition of the body, in fever, consists of an affection of the nervous system, which there is reason to believe is of a peculiar and specific nature, although that nature be at present wholly unknown.

This specific derangement of the nervous system having continued for some time, the vascular system becomes disturbed. How the nervous system so influences the vascular as to bring it into the morbid condition into which it passes, is as unknown to us as the peculiar affection of the nervous system itself. That there is the most close and intimate connexion between these two systems, and that they exert over each other the most important influence both in the state of health and of disease, are in the present state of our knowledge ultimate facts.

With two apparent exceptions, (whether these two cases form real exceptions may still admit of doubt) the vascular derangement connected with, and dependant upon nervous derangement, passes sooner or later into true inflammation. Of this we have the most complete and indubitable evidence—evidence derived both from changes, the known results of inflammatory action, produced in the structure of organs; and from the generation of new products, such as are formed by no other known process but that of inflammation. Almost every change of organic structure which inflammation is ascertained to be capable of producing, is found to take place in fever: almost every product which inflammation is ascertained to be capable of forming, is observed to be generated in fever: it is not possible to doubt, therefore, that the morbid condition into which the vascular system is brought in the progress of fever, is that of inflammation. In what circle of organs inflammation is peculiarly liable to be excited in this disease, by what particular character febrile inflammation is distinguished, and what remarkable differences it exhibits in intensity and extent, have been fully illustrated.

It follows, then, that the second event that takes place in the morbid series constituting fever, is inflammation.