full and equable circulation through it; and where the symptoms are aggravated by the compulsion of a raised posture. The effect of sudden recumbency in relieving faintness is a familiar illustration of this; and conversely, the vertigo which frequently occurs, especially in a weakened state of body, upon suddenly rising from a couch. Headache moreover in some instances is brought on, or much augmented, by the upright posture, and subsides when this is changed. In general we may gather from observation which position of the head is best ;-by the colour of the face, by the state of breathing, and by the action of the heart or other functions, if the patient be unable to express his own sensations. Ferhaps altogether the respiration is the most certain test we can employ in the absence of the latter.

Bleeding by leeches from the hæmorrhoidal vessels might be much more frequently employed than it is in affections of the brain, as well as in those of the spinal cord. I know no mode in which a given quantity of blood can be removed with equal effect in the cases where this is required. It may be difficult to give strict anatomical reasons why this should be so: but what we know on the curious subject of the changes of balance in circulation will at least furnish illustration of it. Nor can I doubt that something here is due to that peculiar relation between the blood in the portal circulation, and the functions and diseases of the brain, of which experience affords so many remarkable proofs. For the practice itself we have especial argument in the frequent alternation of bleeding hæmorrhoids with headaches and other graver affections of the head; and also in the serious effects which sometimes ensue upon the suspension of such discharge, after it has long been habitual to the system.

In the foregoing remarks, particularly those which relate to bleeding in affections of the brain, I have spoken of these

disorders in a way which may seem too general and vague for practical purposes. In explanation of this, I would make one or two remarks. In the first place, I think the object likely to be best fulfilled, of deterring from indiscriminate bleeding, by broadly pointing out the great practical disparity of certain conditions of the brain, which have some appearances in common; and which even produce (though doubtless in different way) some similar effects upon other parts of the body. The attention of the practitioner, if well awake to this distinction, will rescue him from a blind adherence to the one method of instant treatment, so generally in use. It will further direct him to those special indications, -whether derived from the age and general habit of the patient, from the action of the heart and arteries, from the respiration, or from change in the functions of the brain itself,—which may give better and safer guidance to his practice.

Secondly, while fully admitting the value of what has been written on diseases of the brain, and the great advances recently made to their better classification, I can scarcely think the latter object to be yet duly attained.* This remark applies alike to the diseases depending on inflammation of the brain and its membranes; on altered circulation in the organ from other causes; or on extravasation or effusion within the cavity of the cranium. Still more expressly does it apply to lesions, general or partial, of the nervous substance itself. Here the difficulties of exact observation, and ignorance of the func

*It is impossible not to advert here to the valuable work of Dr. Abercrombie, which has done so much towards a right arrangement of these difficult and important diseases. Also to Dr. Bright's Treatise on Diseases of the Brain and Nervous System (vol. ii. of his Medical Reports), in which a very good basis of classification is proposed and followed. And, further, to the Memoir on Injuries of the Brain and its Membranes, by Sir B. Brodie, in vol. xiv. of the Med, Chirurg. Transactions.

tions of particular parts, have hitherto precluded any such intimate knowledge as might furnish a basis for classification and treatment; and we are compelled rather to look to changes in vital condition, than to actual pathological states, in reasoning on the subject.* That there are diseased conditions of the nervous substance, more numerous and varied than those hitherto described, may well be admitted both from analogy, and from notice of effects not easily referrible to any other cause. Nor can it be doubted that many of these will hereafter become known to us; the path for research being widely open, and the methods and instruments of inquiry much better fitted for success than heretofore.

Meanwhile, in this yet imperfect arrangement of cerebral disorders, there is cause for treating of bleeding as a general question of practice, even without express reference to the forms of particular disease. And, from the difficulty as well as importance of this question, it is better perhaps that the medical man should have it constantly before him in this light, than that his judgment should be submitted to rules and nosological distinctions, the application of which to actual disease involves almost as great risk of error as he can incur in proceeding without these technical aids.

* I may instance the question, still undecided, whether the state of ramollissement of the brain can ever occur without preceding inflammation. Dr. Abercrombie's opinion, that there are two distinct causes of this state, is probably that nearest the truth; and the recent microscopical researches of Professor Gluge (Archives de la Médecine Belge, No. I.) would seem to confirm this opinion. The difficulty of obtaining unequivocal proof in these cases is hardly to be understood by those who do not know them on experience. The diagnosis in lesions of the brain is not aided by those external physical signs which have lately obtained such invaluable application to diseases of the chest.

58

CHAP. IV.

ON SUDORIFIC MEDICINES.

Ir must have occurred to the observation of most practitioners, that, of the direct evacuant remedies, sudorifics are amongst those which can least be depended upon; and this even in cases where natural perspiration is one of the symptoms statedly present. It will, I think, be further admitted, that perspiration produced by artificial means rarely corresponds, in the degree of benefit obtained, with that occurring from natural causes :-and, further, that it is a class of remedies where discrimination of effect is singularly vague as regards the several medicines so denominated. These indeed are points which different observers will differently estimate; yet I believe the facts will be so far allowed, as to give some interest to a consideration of their cause.

Does not this uncertainty chiefly depend on mistaken views of perspiration, as a part and symptom of disease? In general opinion, it seems to be regarded as an active cause of change, and usually of amendment, in the existing disorder; and practice is founded for the most part upon this impression. May it not more justly be considered as effect and proof of such change taking place; frequently beneficial in kind, but by no means invariably so? The distinction is obviously important; inasmuch as it involves the question, how far, and by what means, this action is to be sought for as a direct object in the treatment of disease.

In their employment of sudorific remedies, physicians at all times have manifestly dwelt much on the fact, that many

disordered actions, and especially those of the simple febrile paroxysm, and certain of the phlegmasiæ, are suspended in immediate sequel to natural sweating. Proofs as to this mode of inference might be largely drawn from medical writers, were it necessary; nor is the reasoning devoid of plausibility. Setting aside all question of peccant humours, an obvious and general evacuation from the body followed by mitigation of disorder, is a fact in pathology which could never escape notice, and might readily suggest the idea of like advantage from perspiration artificially obtained. Nevertheless, there is great cause to doubt the justness or extent of this inference, and the propriety of much of the practice founded upon it.

In this inquiry, it is needful first to consider, how far the natural action, which it has been sought to imitate, is really remedial in kind. It would advance us very little here to enter into the various theories as to the functions of the capillaries and exhalant vessels. The probable statement seems to be, that what is termed perspiration in the widest sense involves two separate processes; one a mere physical act of simple evaporation of moisture from the surface, the other an act of specific secretion by vital power, and affected therefore expressly by the various states of the circulation and nervous system. The latter is that with which we are here concerned: and, looking to the character of this function, it must be admitted as not impossible that what are called critical sweats may be really the cause of the relief which ensues upon them. But this admission by no means proves the fact to be so; and there are various presumptions, more or less strong, which may be brought against it.

First, the occurrence, often observed, of similar and equal relief under the same course of previous symptoms, without intervening perspiration. This will be familiar to all who