CHAPTER VIII.

DIAGNOSIS.

I cannot conclude this Essay on Fevers, without taking notice of the very great difference there is between the putrid malignant and the slow nervous fever; the want of which distinction, I am fully persuaded, hath often been productive of no small errors in practice, as they resemble one another in some respects, though very essentially different in others. JOHN HUXHAM.

It is plain that there are at least two species of continued fever, both in Europe and this country, and further researches may very possibly show more.

JAMES JACKSON.

TYPHUS fever may be confounded with various other diseases; with pernicious intermittent or remittent fever, with some cerebral affections, with typhoid pneumonia. The most important point, however, in connection with its diagnosis, is that which refers to its relations to typhoid fever. It may be remembered that, in my observations upon the general diagnosis of the latter disease, I alluded to this subject, and expressed the opinion that the two affections constituted radically dissimilar fevers, with the further remark that this question could be best considered after the natural history of both diseases had been given. We are now prepared to enter upon this particular matter, and to establish, as far as this can be done, the differential diagnosis of the two fevers. There is, however, one preliminary remark which ought to be made here, and that is, that even if we should come to the conclusion, as a question of strict scientific and philosophical nosology, that these two affections are essentially and fundamentally alike; that they are forms merely of one individual disease, it would still be hardly less important that we should be able to distinguish between them as forms or varieties of disease. In a practical point of view, the necessity of an accurate diagnosis is not removed, even by the conclusion which I have supposed. These forms of fever, if we choose so to consider them, are still so distinctly marked; they differ, in many respects, so constantly and so widely from each other, that their diagnosis is none the less im

portant than it would be under the other supposition, that they are essentially dissimilar diseases. After pointing out their principal points of resemblance and of dissemblance, I will endeavor to exhibit, as fully and as faithfully as I can, the present state of the question in regard to their identity or non-identity, by a reference to the opinions and the investigations of those observers who have paid especial attention to this subject, constituting as it does one of the most interesting and important which is now occupying the attention of medical men.

SEC. I.-Symptoms. In their mode of access, typhoid and typhus fevers, in many instances, very nearly resemble each other. It is pretty evident, however, that, as a general rule, the access of the disease is more gradual in the former than it is in the latter: typhoid fever creeps on treacherously and obscurely more frequently than typhus does; and the latter makes its onset suddenly, and without any lingering premonitions, more frequently than the former does. The seizure of the typhoid fever, in grave cases, is much more frequently accompanied with abdominal pain and diarrhoea than is that of typhus.

The chief difference between the two diseases, in regard to the strictly febrile symptoms, consists in the more pungent and burning heat of the surface which characterizes typhus. Perhaps it is more frequently the case, also, in this disease than in typhoid fever, that the temperature of the skin falls manifestly below its natural standard as the febrile excitement declines. I am not aware that there is anything in the chills, or in the character of the pulse, to distinguish the two fevers. Perhaps the latter is more uniformly soft and compressible in typhus than in its related disease, and Dr. Gerhard found it more rarely bisferiens, as it is called.

The odor from the body seems to differ in the two diseases. In typhoid fever, when perceived at all, it is usually in the latter period of grave cases, and is then of a stale, cadaverous character; in typhus it is pungent and ammoniacal, more common and more striking.

The thoracic symptoms are subject to greater variety in typhus than in typhoid fever. In some seasons, they are frequent and well marked; in others, they are nearly wanting. In the former disease, they consist generally of dulness on percussion, and feebleness of the respiratory murmur over the lower and back parts of the chest, and of loose mucous rhonchi; in the latter, of dry, sono

rous, or sibilant rhonchi. The cerebral respiration is common to

both fevers.

There is a pretty close correspondence in the number, the severity, and the constancy of the nervous symptoms in the two diseases. Taking in all grades of severity, they may be somewhat more constant and prominent in typhus than in typhoid fever; the pain in the head may be more intense and distressing; the stupor may be more marked; the morbid sensibility of the surface seems to be more common and striking; and the prostration of muscular strength, on the subsidence of the febrile symptoms, is more invariable and profound.

There is one other difference in regard to the existence of which I think there can be no reasonable doubt. The nervous symptoms in typhoid fever almost always creep on more stealthily and gradually than they do in typhus. This is especially true of the dulness and stupor. In the latter disease, this symptom is generally more marked and profound at the commencement than it is in the former.

In the abdominal symptoms of the two diseases there are numerous and important differences. In typhoid fever, where the affection is at all severe, there is generally spontaneous diarrhoea, with liquid, yellowish, ochre-colored stools; in typhus, there is commonly constipation; and the stools, when procured by purgatives, are often dark, slimy, or pitchy, and offensive. Hemorrhage from the bowels is not unfrequent in the former; it hardly ever occurs in the latter disease. Abdominal pains are often present in both fevers, but in the former they almost invariably accompany the diarrhoea; in the latter they are attended by constipation, and are relieved by cathartics. In the former they are more frequently confined to the right iliac region, accompanied by tenderness on deep pressure, and gurgling, than in the latter. Tympanitic distension of the abdomen is very common in typhoid fever; it is very rare in typhus.

The cutaneous eruptions, characteristic respectively of the two affections, are very unlike in many respects. In typhoid fever, the spots are pretty uniformly oval or circular, varying but little in size; often distinctly though slightly elevated; readily disappearing under pressure; generally not very numerous; confined, for the most part, to the skin of the chest and abdomen; and of a bright rose color. In typhus, they are more irregular in their shape and size; not elevated above the adjacent skin; partially disappearing under pressure, or not at all; often abundant, and even confluent;

in many cases occupying the skin of the extremities as well as that of the entire trunk; and usually of a duller and more dusky color than in the former disease. Not unfrequently, also, they consist of true petechiæ, or cutaneous ecchymoses, which in fatal cases persist after death. The average period of their appearance seems to be rather earlier in typhus than in typhoid fever. The dingy color of the skin, the dusky suffusion of the face, and the dark injection of the conjunctiva, are, to a considerable extent, peculiar to typhus. Such are the principal points of likeness, and of unlikeness, in the symptoms of these two diseases. I shall now institute a similar comparison between their respective lesions.

SEC. II.-Lesions. There are some differences in the pathological alterations which are found in the thoracic organs in the two fevers.

The differences in the abdominal lesions in the two diseases are very striking and constant. They are so well marked, and so invariable, that they are easily stated. In typhoid fever, there is a peculiar and constant alteration of the elliptical patches of the ileum, consisting of various degrees of thickening, changes of consistence and color, and especially of ulceration. In typhus, these plates are very rarely altered, and when so at all, only to a very trifling extent. In typhoid fever, the isolated follicles both of the small and the large intestines are found to have undergone, in many cases, the same changes that occur in the aggregated follicles; in typhus, they are in a healthy condition. In the former disease the mesenteric glands, corresponding to the altered and ulcerated follicles, are reddened, softened, and augmented in volume; in the latter they are unchanged in any respect. The large intestines are usually more or less distended with flatus in typhoid fever; they are not so in typhus. The spleen is enlarged and softened in a considerable proportion of cases of both diseases, but these changes are greater and more frequent in the former than in the latter. Alterations in the thickness, color, consistence, and so on, of the mucous membrane of the stomach and intestines are frequent but not invariable in both affections; there is nothing of any diagnostic value in their differences.

SEC. III.-Causes. In connection now with the causes of these fevers, there are several circumstances in which they differ very considerably from each other. Typhus, although occurring most frequently in early life, is not so exclusively confined to this period

as typhoid fever is. The former attacks individuals more than forty years old much oftener than the latter does. Recency of residence in any given place, although it seems to favor the occurrence of typhus, does so much less powerfully and manifestly than of typhoid fever. The unknown causes of the latter disease connected with locality are less circumscribed, geographically, than those of the former; at any rate, they seem to be more constantly and uniformly present over more extensive regions of the earth. In other words, typhoid fever is widely and continually prevalent in many places where typhus is very rarely if ever seen. The sporadic character of the former is more marked and evident than that of the latter. Typhus prevails more frequently in an epidemic form than typhoid fever. The latter disease may be to a certain extent, and under certain circumstances, contagious; but it is much less evidently and decidedly so than the former. The connection. of crowded, filthy, and poorly ventilated apartments, with the origin and propagation of typhus, is more manifest and unequivocal than with those of typhoid fever.

This latter point deserves to be much more strongly and emphatically stated than it was as above in my first edition. It seems to me to constitute a broad, unequivocal, and most striking difference between the two diseases. Typhus fever is very intimately connected, in its etiology, with crowding, impure air, filth, and poverty; it is, to a very great extent, dependent upon these causes for its primary origin. There is no point in its natural history more positively settled than this. Many of the British writers. allege that the entire removal of these causes would exterminate the disease. Now all this is entirely otherwise, so far as typhoid fever is concerned. I do not mean to say that crowding, impure air, filth, and destitution may not sometimes give rise to typhoid fever, and favor its prevalence, although there is very little evidence. if any that they ever act in this manner. But I do mean to say that, as a general rule, the disease is in no way and in no degree dependent upon these causes. In a vast majority of instances it is entirely impossible to trace any connection between them; nay, more than this, it is entirely manifest that there is no such connection. The poison of typhus fever is generated in a stagnant and depraved atmosphere, rank with the thick corruptions of concentrated emanations from the living human body; the poison of typhoid fever, like that of epidemic cholera, and like that of scarlatina, comes we know not whence; it is generated as readily