too anxious to get on with his dialectic, to be interrupted by so trifling a matter as the truth or falsehood of the premisses on which the reasoning rested. What he did in the metaphysical part of his pathology, he also did in its physical part. Although the blood and the nerves are the two leading features of the human economy, he did not search into them by a separate induction; he subjected them neither to chemical experiments in order to learn their composition, nor to microscopic observations in order to learn their structure.224 This is the more observable, because though we must admit that animal chemistry was then generally neglected, and that its real meaning was scarcely understood until the wonderful labours of Berzelius revealed its importance, still the microscope was ready to Cullen's hands; it having been invented a hundred and fifty years before he completed his pathology, and having been in common scientific use for about a hundred years. But his love of synthesis

qualities of bodies as primary and secondary." . . . ." Whether these distinctions be well or ill founded, it is not my business to inquire." But though he did not deem it his business to inquire into the accuracy of these and similar distinctions, he thought himself justified in assuming them, and reasoning from them as if they could explain the working of those sensations, whose perversion formed the point of contact between metaphysics and pathology. See, for instance, in his Works, vol. i. p. 46, the long series of unproved and unprovable assertions respecting the combination and comparison of sensations giving rise to memory, imagination, and the like.

224 Cullen, with that admirable candour which was one of the most attractive peculiarities of his fine intellect, confesses his want of acquaintance with the microscope: "It leaves me, who am not conversant in such observations, altogether uncertain with respect to the precise nature of this part of the blood." Cullen's Works, vol. i. p. 195. A pathologist without a microscope is an unarmed man, indeed. In regard to his animal chemistry, one passage may be quoted as a specimen of the manner in which he arrived at conclusions speculatively, instead of subjecting the phenomena to experimental investigation. "We may remark it to be highly probable, that all animal matter is originally formed of vegetable; because all animals either feed directly and entirely on vegetables, or upon other animals that do so. From hence it is probable, that all animal substances may be traced to a vegetable origin; and therefore, if we would inquire into the production of animal matter, we must first inquire in what manner vegetable matter may be converted into animal?" Cullen's Works, vol. i. pp. 177, 178. The therefore and the must, resulting merely from an antecedent probability, are characteristic of that over-boldness, into which deduction is apt to degenerate, and which is strongly contrasted with the opposite vice of over-timidity, by which inductive reasoners are tainted.

overcame him. His system is constructed by reasoning from general principles; and of that process, he certainly was a consummate master. Between the premisses and the conclusion, he hardly ever lets error creep in. And, in reference to the results of his speculations, he had one immense merit, which will always secure to him a conspicuous place in the history of pathology. By insisting on the importance of the solids, he, one-sided though he was, corrected the equal one-sidedness of his predecessors; for, with extremely few exceptions, all the best pathologists, from Galen downwards, had erred in ascribing too much to the fluids, and had upheld a purely humoral pathology. Cullen turned the minds of men in the other direction; and though, in teaching them that the nervous system is the sole primary seat of disease, he committed a great mistake, it was a mistake of the most salutary kind. By leaning on that side, he restored the balance. Hence, I have no doubt, he indirectly encouraged those minute researches into the nerves, which he would not himself stop to make, but which, in the next generation, gave rise to the capital discoveries of Bell, Shaw, Mayo, and Marshall Hall. At the same time, the old humoral pathology, which had prevailed for many centuries, was practically pernicious, because, assuming that all diseases are in the blood, it produced that constant and indiscriminate venesection, which destroyed innumerable lives, besides the irreparable injury it often inflicted both on body and mind; weakening those whom it was unable to slay. Against this merciless onslaught, which made medicine the curse of mankind, the Solid Pathology was the first effective barrier.225

225 Dr. Watson (Principles and Practice of Physic, 4th edit. London, 1857, vol. i. p. 41) says of the humoral pathology, that "the absurdity of the hypotheses, and still more the dangerous practice which this doctrine generated, began to be manifest, and led to its total abandonment.” But, with every respect for this eminent authority, I venture to observe, that this supposition of Dr. Watson's is contradicted by the whole history of the human mind. There is no well-attested case on record of any theory having been abandoned, because it produced dangerous results. As long as a theory is believed, men will ascribe its evil consequences to any cause except the right one. And a theory which is once established, will always be believed, VOL. II. NN

Practically, therefore, as well as speculatively, we must hail Cullen as a great benefactor of his species; and we must regard his appearance as an epoch in the history of human comfort, as well as in the history of human thought.

It may, perhaps, facilitate the conceptions of unprofessional readers, if I give, in as few words as possible, a specimen of the way in which Cullen employed his method, in investigating the theory of some one class of diseases. For this purpose, I will select his doctrine of fever, which, though now generally abandoned, once exercised more influence than any other part of his pathology. Here, as elsewhere, he reasons from the solids.226 Disregarding the state of the blood, he says, that the cause of all fever is a diminished energy of the brain.227 until there is some change in knowledge which shakes its foundation. Every practical change may, by careful analysis, be shown to depend, in the first instance, on some change of speculative opinions. Even at the present day, many doctrines are generally held in the most civilized countries, which are producing dangerous practical consequences, and have produced those consequences for centuries. But the mischief which the doctrine engenders does not weaken the doctrine itself. Nothing can do that, but the general progress of knowledge, which, by altering former opinions, modifies future conduct.

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226 Some writers, who have taken notice of Cullen, have been deceived in this respect by his occasional use of the expression 'nervous fluid," as if he were willing to let in the idea of humorism. But, in one place, he distinctly guards himself against such misconstruction. "Now, to avoid determining any thing with regard to these opinions, I have used the term of nervous power; but as this is a little ambiguous, I choose to express it by nervous fluid; not that I suppose, with Dr. Boerhaave, that the brain is an excretory, and that a fluid is secreted from it: I mean nothing more than that there is a condition of the nerves which fits them for the communication of motion. But I defer the consideration of these opinions for the present, and perhaps ad Græcas calendas; but nothing shall be rested upon the nervous fluid, it shall be considered merely as a power fitted for communicating motions." Cullen's Works, vol. i. p. 17. Without this passage, his remarks on "the nervous fluid in the brain" (Works, vol. i. p. 129), might easily be misunderstood.

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Together with this, the languor, inactivity, and debility of the animal motions, the imperfect sensations, the feeling of cold, while the body is truly warm, and some other symptoms, all show that the energy of the brain is, on this occasion, greatly weakened; and I presume that, as the weakness of the action of the heart can hardly be imputed to any other cause, this weakness also is a proof of the diminished energy of the brain. So I conclude, that a debility of the nervous power forms the beginning of the cold fit, and lays the foundation of all the other phenomena." Practice of Physic, in Cullen's Works, vol. i. p. 492.

Such diminution may be produced by various sedatives, the most common of which are effluvia, whether marsh or human, intemperance, fear, and cold.228 Directly the energy of the brain is impaired, the disease begins. Rapidly passing through the nervous system, its first palpable effect is a chill, or cold fit, which is accompanied by a spasm on the extremities of the arteries, particularly where they touch the surface of the body.229 This spasm on the extreme vessels, irritates the heart and arteries, and the irritation continues till the spasm is relaxed.230 At the same time, the increased action of the heart restores the energy of the brain; the system rallies; the extreme vessels are relieved; while, as a consequence of the whole movement, sweat is excreted, and the fever abates.231 Shutting out, therefore,

228 To render our doctrine of fever consistent and complete, it is necessary to add here, that those remote causes of fever, human and marsh effluvia, seem to be of a debilitating or sedative quality." "Though we have endeavoured to show that fevers generally arise from marsh or human effluvia, we cannot, with any certainty, exclude some other remote causes, which are commonly supposed to have at least a share in producing those diseases. And I proceed, therefore, to inquire concerning these causes; the first of which that merits attention, is the power of cold applied to the human body." ... "Besides cold, there are other powers that seem to be remote causes of fever; such as fear, intemperance in drinking, excess in venery, and other circumstances, which evidently weaken the system. But whether any of these sedative powers be alone the remote cause of fever, or if they only operate either as concurring with the operation of marsh or human effluvia, or as giving an opportunity to the operation of cold, are questions not to be positively answered." Practice of Physic, in Cullen's Works, vol. i. pp. 546, 552. One part of this view has been corroborated, since the time of Cullen. "The experiments of Chossat and others clearly prove cold to be a direct sedative." Williams' Principles of Medicine, second edit. London, 1848, p. 11. Compare Watson's Principles and Practice of Physic, 4th edit. London, 1857, vol. i. pp. 87-92, 249. Hence, perhaps, the "irresistible tendency to sleep caused by exposure to severe or long-continued cold." Erichsen's Surgery, second edit. London, 1857, p. 336; but as to this, Dr. Watson (Principles of Physic, vol. i. p. 89) is sceptical, and thinks that, in those cases which are recorded, the drowsiness ascribed to cold, is, in a great measure, the result of fatigue.

229 Cullen's Works, vol. i. p. 493. Compare, respecting his general theory of spasm, p. 4, and vol. ii. p. 400.

230 The idea of fever, then, may be, that a spasm of the extreme vessels, however induced, proves an irritation to the heart and arteries; and that this continues till the spasm is relaxed or overcome." Cullen's Works, vol. i. p. 494.

231 Such, however, is, at the same time, the nature of the animal economy, that this debility proves an indirect stimulus to the sanguiferous

all consideration of the fluids of the body, the successive stages of languor, cold fit, and hot fit, might, in Cullen's opinion, be generalized by reasoning merely from the solids, which, furthermore, produced his well-known distinction between fevers, the continuance of which is owing to an excess of spasm, and those, the continuance of which is owing to an excess of debility.232

A similar process of thought gave birth to his Nosology, or general classification of diseases, which some have regarded as the most valuable part of his labours ;253 though, for reasons already mentioned, we must, I think, reject all such attempts as premature, and as likely to work more harm than good, unless they are simply used as a contrivance to aid the memory. At all events, the Nosology of Cullen, though it exhibits clear traces of his powerful and organizing mind, is fast falling into dis

system; whence, by the intervention of the cold stage and spasm connected with it, the action of the heart and larger arteries is increased, and continues so till it has had the effect of restoring the energy of the brain, of extending this energy to the extreme vessels, of restoring, therefore, their action, and thereby especially overcoming the spasm affecting them; upon the removing of which, the excretion of sweat, and other marks of the relaxation of excretories take place." Practice of Physic, in Cullen's Works, vol. i. pp. 501, 502. See also p. 636, § cciii. Or, as he elsewhere expresses himself (vol. i. p. 561): "With regard to the event of fevers, this is the fundamental principle: in fevers, nature cures the disease; that is, certain motions tending to death continue the disease, but, in consequence of the laws of the animal economy, other motions are excited by these which have a tendency to remove it.'

232 If we may trust to our conclusions with respect to the proximate cause, it follows, most naturally, from the view there given, that the continued fever is always owing to an excess of spasm, or to an excess of debility as the one or other of these prevails, it will give one or other of the two forms, either the Synocha or inflammatory fever, or the Typhus or nervous fever." Cullen's Works, vol. i. p. 518.

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"Cullen's most esteemed work is his Nosology. "Hamilton's History of Medicine, London, 1831, vol. ii. p. 279. "His Nosology will probably survive all his other works; it is indisputably the best system which has yet appeared." Lives of British Physicians, London, 1830, p. 213. "Celle de Cullen, qui parut en 1772, et qui constitue un véritable progrès." Renouard, Histoire de la Médecine, Paris, 1846, vol. ii. p. 231. See also Hooper's Medical Dictionary, edited by Dr. Grant, London, 1848, p. 937. But, in the most celebrated medical works which have appeared in England during the last twelve or fifteen years, I doubt if there is any instance of the adoption of Cullen's nosological arrangement. Abroad, and particularly in Italy, it is more valued.