a. In fever the delirium is very often of a quiet character, with considerable prostration, inattention to surrounding objects, and unconnected muttering and rambling ; sometimes, however, the patient is very noisy and excited, and can scarcely be kept in bed, and this especially happens when the functions of the liver are disordered. It follows upon the insomnia of the early stages. coming on at first only at night, and continuing throughout to have nocturnal exacerbations ; there is great insensibility to external impressions, and fre quently marked deafness. In addition to these characters of the delirium. there are the special indications of fever as distinct from those of inflamma tion; the eyes are dull 9.nd suffused, not brilliant and ferrety, the movements are feeble and tremulous, and the pulse is essentially weak and soft : these characters have been already detailed. (See Chap. IV. 1, Continued Fever.) b. In delirium tremens it is accompanied by peculiar, hurried movements and muscular tremor; but there is also something in the character of the delirium quite distinctive ; the mind generally runs upon one subject which is attended with anxiety or distress, either upon some business engagement which cannot be fulfilled, or on the presence of some disagreeable or disgust ing object—some creature crawling about the bed, some horrible death's head staring at the patient It is a busy and active, but not a violent. delirium ; the patient is gesierally ready enough to do as he is told, will for the moment, perhaps, abandon his imaginary pursuit to answer questions apparently in a rational manner, and pat out his tongue when desired ; but quite as often he still keeps hold of the bedclothes under the idea that they are some other object, and while answering the questions addressed to him, continues to issue orders to some of his imagmary subordinates. There is always great restless ness ; getting out of bed, pulling about the bedclothes, constant talking, gene- ' rally in a loud tone of voice, the same definite object always predominating in the mind, to the entire exclusion of surrounding,realities. Sleeplessness is an invariable precursor of this form of delirium, preceding by some days its full development, but the nocturnal exacerbations are rarely so marked as in fever.
The moist, creamy tongue, the soft pulse, and perspiring skin are most im portant indications, because they not only materially aid the diapoais, but form the basis of rational treatment.
c. The delirium of pneumonia very closely resembles that of fever ; but when it occurs in persons of dissipated habits, may more nearly approach to delirium tremens ; just as happens when such persons meet with severe inju ries, or suffer. from erysipelas or rheumatism. Hence the delirium itself does not aid our diagnosis, inasmuch as its causes, and consequentiy its manifesta tions, are so analopus : when resembling that of fever, the pneumonia has an &dynamic type like the common continued fever of the present day, and to the accompanying condition of the blood the delirium is due ; while, vrhen it approaches in character to delirium tremens, the impresaion made on the nervous system by habits of dissipation acts as the predisposing cause, and the pneumonia merely takes the place of any other depressing influence in exciting the delirium.
The important point in diaposis is, that the pneumonia should not be over looked ; and a correct opinion will in all cases very much depend on systematic investiption, when delirium is present along with internal inflammation. The
history must be carefully inquired into, the general symptoms weighed, arid the conditions of all the organs closely examined into. In the absence of more decided symptoms, quick breathing, a dusky flush on the face, and especially rusty sputa, are unlike fever ; dryness of the tonpe and smallness of the pulse, unlike pnnine delirium tremens.
Inflammation of the heart is another important condition which must be sought for in obscure cases of delirium. It is probable that, in cases where this has been found as the sole evidence of disease, the true explanation is rather to be sought in the association which has next to be studied.
d. Delirium supervening in the course of acute rheumatism and erysipelas. These forms of delirium may be taken together, because there is alleged to be in each an occasional metastasis to the brain ; in the latter the preceding state e,amiot be mistaken, but in the former the occurrence of inflammation of the heart may be accompanied by a retrocession of the affections of the joints, or may even be almost the only organ which rheumatism attacks ; in the present state of our knowledge we must look upon idiopathic inflammation of that °Tan as being at least extremely rare.
It is quite certain that delirium of a very active character may occur in both these disorders without any inflammation of the brain. In acute rheu matism it generally commences as a slight wandering at night, or is at first' only marked by some peculiarity of manner ; it then passes rapidly into deli rium of a noisy kind, which is often accompanied by great obstinacy and re fusal to answer questions or to take food and medicine, and sometimes by local or general spasm ; after &partial or complete remission, the delirium is apt to recur, and it then passes, m fatal cases, into coma and death. In erysipelas, it has a less active character generally ; it has much analogy to that observed in fever ; beginning with the same wandering at night, it passes flito the low muttering and rambling form, and rarely assumes a noisy character ; in fatal eases, this also 'terminates in coma. In persons of dissipated habits and dila pidated constitutions, the delirium attendant on both of these diseases more commonly simulates delirium tremens ; and this is an important point in diag nosis, because it decides the question at once of whether there be inflamma tion of the brain or not. It is certain, under such circumstances, that the delirium is not due to metastasis.
Metastasis, in the true sense of the word, must be exceedingly rare in ery sipelas ; it may be conceived, but is not known as part of its clinical history; I mean the disappearance of the swelling and redness of the part coincidently with the incursion of head4ymptoms. On the other hand, considering the nature of the disease, that it is not associated with exudation of lymph but of serum, it is quite possible that serous effusion may be due to extension of erysipelatons inflammation to the membranes of the brain ; but it is quite as probable that the delirium is merely the evidence of altered conditions of blood, of the circulation, and of the nervous energy, as in the other forms already noticed; and this is the more likely, because it exists without as well as with effusion. In diagnosis, we have only to remember that the delirium of ery sipelas is not associated with inflammation of the structure of the brain, or with such inflammation of its membranes as leads to effusion of lymph or of pus ; because this is the all-important point in treatment.