PART I.

ACUTE DISEASES.

CLASS I. FEVERS.

CHAP. I.

GENERAL DOCTRINE OF FEVER.

Importance of the Subject. Characters of Pyrexia. Of Rigors and heat of skin. Frequency of Pulse. Loss of muscular power. Other functions disturbed in Fever. Leading divisions of febrile Diseases. Causes of Fever, predisposing and occasional. Nature of Fever. Periodic movements observable in Fever. Doctrine of critical days. Principles of the treatment of Fever.

FEVER is the most important, because the most universal and the most fatal of all the morbid affections of which the human body is susceptible. Its presence characterizes a great number of diseases; and in others which are not for the most part attended by it, the physician must always be prepared to expect its occurrence. It is that, by the presence or absence of which all his views of treatment are to be regulated, whose rise, progress, and termination, he always watches with the closest attention, and by the degree of which present, he is enabled in a great measure to estimate the danger in each particular case. Some idea may be formed of the great mortality of fever from the statements of Sydenham, who calculated that two-thirds of mankind die of acute diseases properly so called, and two-thirds of the remainder of that lingering febrile disease, consumption. Fever has proved a fertile theme, on which the ingenuity of physicians in all ages has been exerted. Indeed the attention which it has received from every medical author, both ancient and modern, would alone be sufficient to impress upon any one the importance of the doctrines it embraces. How difficult, lastly, is the study of fever may be inferred from this, that though so much has been written concerning it, there is

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subject in the whole circle of medical science which still involves so many disputed points. In every view the doctrines of fever must be considered of paramount importance, and they constitute therefore, with great propriety, the foundation of all pathological reasoning.

When a person is suddenly attacked by shiverings or rigors, followed by a hot skin, a quick pulse, and a feeling of languor and lassitude, he is said to have an attack of fever. With such symptoms are usually present also thirst and impaired appetite, restlessness, and diminished secretion. These constitute the six leading symptoms of fever or pyrexia-the characteristic features by which its presence may always be detected. Every function of the body indeed is more or less disturbed, but we select for the definition of fever those which are of the most importance in the animal oeconomy. The marks of disturbance in them afford the six characters of fever just enumerated, and of which we now propose to treat in detail.

CHARACTERS OF PYREXIA.

1. Chilliness, succeeded by increased heat of skin, is the first and leading feature of fever. The chilliness or rigor is sometimes so slight as almost to escape the notice of the patient. At other times it is exceedingly violent, so that he complains bitterly of cold. His teeth chatter. His limbs tremble. The skin is pale, rough, and contracted. The features shrink. A sensation is felt as of cold water trickling down the back. By degrees the chilliness subsides, and begins to alternate with warm flushings. A heat of skin greater than natural succeeds, and with it returns the colour of the skin. The cheeks become even flushed, and the eyes suffused. The features recover their usual size, or appear more turgid than in health. The hot stage of fever is then said to be formed, which may go off in a few hours, as in the case of an ague, or may continue for days or weeks, as in common continued fever.

The duration of the cold stage varies from an hour to two or even three days. Though often very slight, it is perhaps never entirely wanting; and it is at all times to be carefully inquired for and noted by the physician, as marking the precise period of the accession of fever. This it is useful to know in all febrile diseases; but in some, as small-pox and measles, it forms the basis of our prognosis. The coldness of which the patient

complains is sometimes, though not always, perceptible to the touch of another, but never to the extent that might have been anticipated from the sufferings and expressions of the patient.

2. The second great feature denoting the presence of fever is an increase in the frequency of the pulse. This is one of the earliest and most constant of all the symptoms of fever, and perhaps would scarcely ever be wanting, but for some accidental circumstance, such as a congestion of the blood in the vessels of the brain or liver. The feverish pulse of an adult varies in point of frequency, from the slightest increase above the natural standard, to that point at which it can with difficulty be numbered.* In forming any judgment of diseases by the frequency of the pulse, great allowance must always be made for the age of the patient-for sex, constitution, and temperament of body-for the kind and period of the disease-for external circumstances; such, for instance, as the state of the air surrounding the patient, and the irritations to which he is exposed-for the effect of diet and medicines-and lastly, under circumstances of great exhaustion, the mere position of the body. The pulse of fever differs from that of health in other points, besides that of comparative frequency. These characters of the febrile pulse are distinguished by the terms hardness, wiriness, fulness, and weakness; but as they are not essential to the existence of fever, they will more properly come under consideration hereafter.

Of these leading characters of fever, rigor, succeeded by heat of skin, and increased frequency of pulse, it is curious to observe what different judgments have been formed. The bulk of mankind have almost uniformly and by common consent laid the greatest stress upon the increased heat of the body, and accordingly all the expressions for fever in different languages are derived from words signifying heat or fire. This

For practical purposes it may be advisable for the student to make some rude divisions of feverish pulses. The first may have 84 in a minute for its average, and range between the natural standard and 90. This is the pulse of common fever. The second may have 96 for its average, and its range will be from 90 to 100. This is the pulse of inflammatory fever. The third 110, ranging between 100 and 120. This is the pulse of typhoid fever. The last, which may have 132 for its average, is observed in the advanced stages of hectic fever. The utmost limit of frequency at which a pulse can be correctly counted, is 144, being double the number of its healthy pulsations.

was for a long time also the doctrine of the schools, Galen having taught that the essence of fever consisted in præternatural heat. Boerhaave, who investigated the phenomena of fever with great accuracy, and acknowledged the importance of these leading symptoms, yet imagined that the quickened pulse was the single essential symptom of fever, uniformly present from the beginning to the end of the disease, and by which the physician judges of its presence or degree. In this opinion may be traced the early bias in favour of mathematical medicine which distinguished this excellent physician. Dr. Cullen, on the other hand, placed the rigor and shivering in the first rank of febrile symptoms. He imagined that as the hot stage of fever is so constantly preceded by the cold stage, the one was caused by the other, and the cause of the cold stage therefore the cause of all that followed in the course of the paroxysm. These opinions we may be allowed to consider as upon a par in point of relative merit. They may all be supported by specious arguments, but we must end by confessing that fever does not consist in this or that symptom, but in the co-existence and succession of many.

3. Among the various evidences of the presence of fever, the loss of muscular power was noticed, marked by the occurrence of languor and lassitude, a sensation of fatigue, and great pain referred to the muscles and joints, particularly of the back and limbs. The patient feels as if beaten with sticks. This striking index of fever was elegantly illustrated by Boerhaave, under the title of debilitas febrilis. It is to be distinguished from that weakness of muscle which arises from great exertion, the privation of nourishment, or the violence or long continuance of an evacuation. It is present in a greater or less degree in all fevers, though it bears no proportion to the violence or danger of the disease. It is aggravated by the slightest exertion of muscular power, and in severe cases is but partially relieved by the horizontal posture.

4. Disturbances in the functions of animal heat, circulation, and muscular motion, afford then the most prominent marks of fever; but every other function of the body, animal, vital, and natural, is more or less deranged, and that of the appetites in so remarkable a degree, as to demand particular notice. The appetite for solid food is diminished, while that

for liquids is increased. In severe cases of fever there is an absolute loathing of food, accompanied often with nausea and vomiting. Thirst is one of the most familiar of all the characters of fever, and yet one more frequently wanting than any other. The desire is almost invariably for cold drink, and doubtless this is a beautiful provision of nature. There is no ground whatever for believing with Asclepiades, and the followers of his school, that any danger is to be apprehended from the indulgence of this appetite.

5. The restlessness and want of sleep which occur in febrile diseases are characteristic symptoms, which deserve notice. They are seldom wanting in the early stages of fever, and are peculiarly distressing to the patient, often continuing during the whole course of a long fever. If the patient dozes for a time, his dreams are harassing, and he wakes unrefreshed. The return of sleep is one of the surest indications of convalescence.

6. Nothing more strikingly characterizes the presence of fever than a general diminution and depraved state of the secretions all over the body. This is exemplified in the dryness and clamminess of the mouth, and the white and furred tongue, which are so frequently observed in all febrile diseases. The skin is dry and parched from the cessation of cuticular transpiration. The urine is scanty and high coloured. The bowels are generally constipated. The evacuations which may be procured are, for the most part, dark and fætid, owing, as we may presume, in a great measure, to the diminished quantity and vitiated quality of the bile. These and several other phenomena of fever are referrible to the important general principle now laid down.

The restoration of secretion is generally considered as the test of the decline of fever, and hence it is that in Sauvage's excellent and philosophical definition of fever,* we find the terms cum madore cutis in declinatione. This, however, is not applicable unless such change be general over the body. Occasional perspirations are rather evidences of the continuance of the febrile state, and as such frequently become the direct guides of our treatment.

Pulsus magnitudo et frequentia, cum frigore in insultu, fervore in decursu, madore in declinatione, et semper virium prostratione majori quam a virium vitalium gradu foret expectandum.