the normal condition return. It is the same when pathological injuries are healed; the trouble in the intelligence ceases, and reason comes back. Pathology here, too, furnishes us with a kind of functional analysis and synthesis, just as may be observed in experiments of reproduction. Disease, in a word, suppresses the function more or less entirely, by changing more or less completely the texture of the organ, and the cure restores the function by reestablishing the normal organic condition.
If the manifestations of the brain's functions were the earliest to attract the attention of philosophers, they will assuredly be the last to receive explanation from physiologists. We believe that the progress of modern science allows us now to approach the subject of the physiology of the brain; but, before beginning the study of the cerebral functions, we must clearly understand our point of departure. In this essay, we have attempted to state only one term of the problem, and to show how untenable is the opinion that the brain forms an exception in the organism, and is the substratum of intelligence instead of being its instrument. This idea is not merely an obsolete conception, but an unscientific one, injurious to the progress of physiology and psychology. Indeed, what sense is there in the notion that any apparatus of Nature, whether in its lifeless or its living domain, can be the seat of a phenomenon without being its instrument? Preconceived ideas clearly have a great influence in discussing the functions of the brain, and a solution is combated by arguments used for the sake of their tendency. Some refuse to allow that the brain can be the organ of intelligence, from fear of being involved by that admission in materialistic doctrines; while others eagerly and arbitrarily lodge intelligence in a round or fusiform nerve-cell, for fear of being charged with spiritualism. For ourselves, we are not concerned about such fears. Physiology tells us that, except in the difference and the greater complexity of the phenomena, the brain is the organ of intelligence in exactly the same way that the heart is the organ of circulation, and the larynx that of the voice. We discover everywhere a necessary bond between the organs and their functions; it is a general principle, from which no organ of the body can escape. Physiology should copy the example of more advanced sciences, and free itself from the fetters of philosophy that would impede its progress; its mission is to seek truth calmly and confidently, its object to establish it beyond doubt or change, without any alarm as to the form under which it may make its appearance.
