of popular good sense, which arrives at its conclusions by essentially similar, though less regular and guarded, processes. And this authority deserves to be treated with special respect in regard to the subject of human nature, so long and habitually the object of general contemplation and reflection. Many just notions respecting it are embodied in proverbs and other common sayings, and even in individual words, which often indicate a remarkable sagacity in the apprehension of real relations.

As to the second resource, bearing in mind the general biological principle of Broussais, that the morbid state does not differ radically from the normal, but is only an exaggeration or reduction of some of its elements beyond the limits of variation habitually proper to them, we see what important aid may be rendered by the study of insanity in its several forms and degrees. Such cases, in fact, supply spontaneous experiments, where we should be debarred from instituting artificial ones. And we are thus enabled to watch the manifestations of a particular faculty or moral tendency, acting in an intensified degree, and uncontrolled by thoughts and feelings by which it is habitually directed or restrained. And, as to the third resource, it being true that the higher animals present, in broad outline, though in various degrees, the same fundamental qualities and tendencies as man, their study offers the same advantages for the

investigation of his moral and intellectual nature as Comparative Physiology furnishes in general biological research. This comparison with the other members of the animal series will be especially useful in determining the really innate and universal attributes of Man, unmodified by systematic cultivation or social influences. Any moral propension or intellectual function alleged to be a constituent element of human nature, but totally absent in the other higher zoological types, must be disallowed as an elementary principle and regarded as a complex result of artificial culture or of the social relations.*

It is to be remembered that the cerebral functions, from the biological point of view, with which we are here concerned, are regarded only with relation to the primary destination of animal life generally, as aiding and facilitating vegetative life, by procuring materials and avoiding dangers. Man has been described as "an intelligence served by organs"; but he might more justly be characterised, with respect to his original and fundamental position, as "a group of organs served by an intelligence." This relation, it is true, afterwards tends to be inverted, at least in the higher human types; but such in

* See the remarkable Lettres sur les Animaux of Georges Leroy, edition of 1862, with an excellent preface by Dr. Robinet. An English translation appeared in 1870. This work is in the Bibliothèque Positiviste, and Leroy's name is in Comte's Historic Calendar.

version (never more than partial) is the result of the prolonged and continuous action of the social state on the individual members of the race. When we study Man under the head of Biology, we provisionally abstract from those social influences, which remain to be considered at a later stage of our inquiries. They belong to the province of Moral Science, which is posterior to Sociology in the Encyclopedic scale, and presupposes its results. The principal importance, indeed, of the study of Cerebral Physiology lies precisely in the fact, that at least a first outline of it is a necessary preliminary to Sociology, which requires as its foundation this partial study of the units whose combined action and continuous development it has to exhibit. But even for such partial study the subsequent reaction of Sociology is most valuable; for, the nature and working of the propensions and faculties being identical in the individual and the species, they can be viewed on a larger scale, and therefore more distinctly seen in the history of the human race than by observation of their personal manifestations. When we come to construct moral theory on the basis of Sociology, we must return to the consideration of the affective and intellectual functions of Man, and we shall then be able to regard them from a higher than the merely biological point of view, as exercised, cultivated and enlarged by the social evolution.

Though the primary object of the present study

is to exhibit a draught of our elementary powers and tendencies, as distinct from a determination of the corresponding cerebral organs, it must be always kept in view that the latter is indispensable to the scientific completeness of the biological theory of Human Nature. Every function which is proved to exist must have its own organ in the brain, the determination of which, though it may be postponed, is a task which cannot be indefinitely left unaccomplished. Here, as in every branch of Biology, a correspondence between organ and function must be established; neither the anatomical nor the physiological aspect can permanently stand alone, whatever precious instruction either, especially the latter, can singly furnish. Gall, when laying the foundations of Cerebral Physiology, was forced to attempt a detailed scheme of localisation of the functions, in order to be able to propose a doctrine. capable of general discussion. This was a perfectly legitimate exercise of the right of forming scientific hypotheses, which is limited only by the condition that they should be ultimately verifiable. But the effort was premature, and his scheme, as a whole, was certainly a failure, though it contains many elements likely in the end to find acceptance. What is now insisted on is that we must always carry with us the conviction that, to every elementary function of whose existence there is adequate proof, there corresponds in the cerebral apparatus a definite organ, real, though—it may be at present unassignable.

We say "to every elementary function"; for there can be no doubt that in cerebral action several organs habitually take part in producing a result, sometimes in the way of concurrence, and sometimes in that of conflict. This is obvious in the case of different affective impulses, and as between those impulses and intellectual acts. And it will be seen hereafter that the scholastic facultiesreason, judgment, imagination, and the like—are really composite, the result of the simultaneous operation of more organs than When we have arrived at a definite number of elementary (or irreducible) propensions and faculties, it will remain to show how, by their various combinations, states of feeling and thought are produced which a hasty speculator would be apt to attribute to the action of a single organ. The followers of Gall have undoubtedly multiplied, without necessity, hypothetic organs, especially, as we shall see, in the department of intellect. For the rectification of these errors, we shall require a more thorough study than has yet been carried out of the sympathies and synergies—as well as the antagonisms—of the different constituents of our moral and intellectual nature.

Another preliminary observation must here be made as to the necessity of recognising the reaction of the vegetative viscera on the cerebral functions. This was not sufficiently attended to by Gall, and thus his construction was injured by its too great