timately connected with the other; and eventually, no doubt, both will be fused into a single study, by discovering laws which will prove that here, as elsewhere, nothing is really abnormal, or irregular. Hitherto, however, the physiologists have immeasurably outstripped the pathologists in the comprehensiveness of their views, and, therefore, in the value of their results. For, the best physiologists distinctly recognize that the basis of their science must include, not only the animals below man, but also the entire vegetable kingdom, and that, without this commanding survey of the whole realm of organic nature, we cannot possibly understand even human physiology, still less general physiology. The pathologists, on the other hand, are so much in arrear, that the diseases of the lower animals rarely form part of their plan; while the diseases of plants are almost entirely neglected, although it is certain that, until all these have been studied, and some steps taken to generalize them, every pathological conclusion will be eminently empirical, on account of the narrowness of the field from which it is collected.

The science of pathology being still so backward in the conception as well as in the execution, that even men of real ability believe that it can be raised from a mere study of the human frame, it will hardly be expected that the Scotch, notwithstanding the marvellous

tomy will be imperfectly appreciated, and its true relation to physiology will remain undefined. Inasmuch, however, as, with our actual resources, the most careful dissection is often unable to detect (in insanity, for instance) those changes of structure which produce changes of function, superficial thinkers are placed under a strong temptation to deny their invariable connexion; and while the microscope is so imperfect, and chemistry so backward, it is impossible that experiments should always convince them of their mistake. Hence, I believe that until our means of empirical research are greatly improved, all such investigations, notwithstanding their immense value in other respects, will tend to lead mere inductive minds into error, by making them rely too much on what they call the facts of the case, to the prejudice of the reason. This is what I mean by saying, that our knowledge is not sufficiently advanced to make it advisable to divide the sciences of organic bodies into physiological and anatomical. At present, and probably for some time yet, the humbler division into physiological and pathological, may be deemed safer, and more likely to produce solid results.

boldness of their speculations, should have been able, in the eighteenth century, to anticipate a method which the nineteenth century has yet to employ. But they produced two pathologists of great ability, and to whom we owe considerable obligations. These were, Cullen and John Hunter.207 Cullen was eminent only as a pathologist; but Hunter, whose fine and discursive genius took a much wider range, was great both in physiology and in pathology. A short account of their generalizations respecting organic science, will be a fitting sequel to the notices I have already given of what was done by their countrymen for inorganic science, during the same period. It will complete our survey of the Scotch intellect, and will enable the reader to form some idea of the brilliant achievements of that most remarkable people, who, contrary to the course of affairs in all other modern nations, have shown that scientific discoveries do not necessarily weaken superstition, and that it is possible for two hostile principles to flourish side by side, without ever coming into actual collision, or without sensibly impairing each other's vigour.

In 1751, Cullen was appointed professor of medicine in the University of Glasgow;208 from which, however, in 1756, he was removed to the University of Edinburgh,209 where he delivered those celebrated lectures, on which his fame now depends. During the early part of his career, he paid great attention to inorganic physics, and propounded some remarkable speculations, which are supposed to have suggested the theory of latent heat to Black, who was his pupil.210 But, to

207 Hunter, as we shall presently see, did take an extraordinarily comprehensive view of pathology, including the whole of the organic world, and even the aberrations of form in the inorganic.

209 Thomson's Life of Cullen, vol. i. p. 70, Edinburgh, 1832.

209 Thomson's Life of Cullen, vol. i. p. 96. Bower states that Cullen 66 was appointed to the chair in 1755." Bower's History of the University of Edinburgh, vol. ii. p. 216, Edinburgh, 1817.

210 It seems impossible to peruse the passages I have quoted from Dr. Cullen's manuscript lectures and papers, and from his Essay on Evaporation, without perceiving that his investigations with regard to the heat and cold occasioned by the combination, liquefaction, and evapora

follow out those views, would have required a number of minute experiments, which it did not suit the habit of his mind to make. Having, therefore, put forth his ideas, he left them to germinate, and passed on to his arduous attempt to generalize the laws of disease as they are exhibited in the human frame. In the study of disease, the phenomena being more obscure and less amenable to experiment, there was greater latitude for speculation; hence, he could more easily indulge in that love of theory, which was his ruling passion, and with an extreme devotion to which he has been reproached.211 That the reproach is not altogether unjust, must, I think, be admitted, since we find him laying down the doctrine, that, inasmuch as, in the treatment of disease, theory could not be separated from practice, it was unimportant which came first.212 This was tantamount to saying, that a medical practitioner might allow his theories to control his observations; for it is certain that, in an immense majority of cases, men are so tenacious of the opinions they imbibe, that whatever, in any pursuit, first occupies their understanding, is likely to mould all that comes afterwards. In ordinary minds, associations of ideas, if firmly established, become indissoluble; and the power of separating them, and of arranging them in new combinations, is one of the rarest of our endowments. An average intellect, when once possessed by a theory, can hardly ever escape from it. Hence, in practical matters,

tion of bodies, must not only have assisted to direct the attention of his pupil Dr. Black to similar inquiries, but must also have furnished him with several of the data from which his simple and comprehensive theory of Latent Heat was afterwards so philosophically deduced." Thomson's Life of Cullen, vol. i. p. 56.

211 "It is allowed by the admirers of this great man, that he was perhaps too fond of theory." Bower's History of the University of Edinburgh, vol. iii. p. 278.

212 In 1759, he wrote to Dr. Balfour Russell, one of his favourite pupils: "You will not find it possible to separate practice from theory altogether; and therefore, if you have a mind to begin with the theory, I have no objection." Thomson's Life of Cullen, vol. i. p. 130. Compare his Introductory Lectures to the Practice of Physic, where, asserting truly, reasoning in physic is unavoidable" (Cullen's Works, vol. i. p. 417), he boldly infers "that to render it safe, it is necessary to cultivate theory in its full extent."

that

theory should be feared, just as, in scientific matters, it should be cherished; because practical pursuits are chiefly engrossed by the lower class of minds, where associations and the force of prejudice are extremely strong, while scientific pursuits concern the higher class, where such prepossessions are comparatively weak, and where close associations are more easily severed. The most powerful intellects are most accustomed to new arrangements of thought, and are, therefore, most able to break up old ones. On them, belief sits lightly, because they well know how little evidence we have for many of even our oldest beliefs. But the average, or, as we must say, without meaning offence, the inferior, minds, are not disturbed by these refinements. Theories, which they have once heartily embraced, they can hardly ever get rid of, and they often dignify them with the name of essential truths, and resent every attack upon them as a personal injury. Having inherited such theories from their fathers, they regard them with a sort of filial piety, and cling to them as if they were some rich acquisition, which no one has a right to touch.

To this latter class, nearly all men belong, who are more engaged in practical pursuits than in speculative ones. Among them, are the ordinary practitioners, whether in medicine or in any other department, extremely few of whom are willing to break up trains of thought to which they are inured.213 Though they profess to despise theory, they are, in reality, enslaved by it. All that they can do, is to conceal their subjection, by terming their theory a necessary belief. It must, therefore, be deemed a remarkable proof of Cullen's love of deductive reasoning, that he, sagacious and clear-sighted

213 Even Cullen himself says, rather roughly, "The great horde of physicians are always servile imitators, who can neither perceive nor correct the faults of their system, and are always ready to growl at, and even to worry, the ingenious person that could attempt it. Thus was the system of Galen secured in the possession of the schools of physic, till soon after the irruption of the Goths and Vandals destroyed every vestige of literature in the western parts of Europe, and drove all that remained of it to seek a feeble protection at Constantinople." Lectures introductory to the Practice of Physic, in Cullen's Works, vol. i. p. 386, Edinburgh, 1827.

as he was, should have supposed that, in so practical an art as medicine, theory could, with impunity, precede practice. For, it is most assuredly true, that, taking men in the average, their minds are so constructed, that it cannot precede it without controlling it. It is equally true, that such control must be hurtful. Even now, and notwithstanding the great steps which have been taken in morbid anatomy, in animal chemistry, and in the microscopic investigation both of the fluids and solids of the human frame, the treatment of disease is a question of art, far more than a question of science. What chiefly characterizes the most eminent physicians, and gives them their real superiority, is not so much the extent of their theoretical knowledge,-though that, too, is often considerable, but it is that fine and delicate perception which they owe, partly to experience, and partly to a natural quickness in detecting analogies and differences which escape ordinary observers. The process which! they follow, is one of rapid, and, in some degree, uncon scious, induction. And this is the reason why the greatest physiologists and chemists, which the medical profession possesses, are not, as a matter of course, the best curers of disease. If medicine were a science, they would always be the best. But medicine, being still essentially an art, depends mainly upon qualities which each practitioner has to acquire for himself, and which no scientific theory can teach. The time for a general theory has not yet come, and probably many generations will have to elapse before it does come. To suppose, therefore, that a theory of disease should, as a matter of education, precede the treatment of disease, is not only practically dangerous, but logically false. With its practical danger, I am not now concerned; but its logical aspect is a curious illustration of that passion for systematic and dialectic reasoning which characterized Scotland. It shows that Cullen, in his eagerness to argue from principles to facts, instead of from facts to principles, could, in the most important of all arts, recommend a method of procedure, for which even our knowledge is