Page:Popular Science Monthly Volume 73.djvu/78

74 "Rapports" show. Nevertheless, later materialists find warrant for their most striking metaphor in his pages. As the liver secretes bile and the kidneys urine, so the brain secretes thought; thus ran Karl Vogt's raucous challenge (1847). Cabanis employed the very phrase "secretion of thought" which, as his editor, Peisse, says, "has remained celebrated." But the classical passage, also in the the "Rapports," reads as follows: "In order to arrive at a correct idea of those operations from which thought arises, we must consider the brain as a particular organ, destined specially to produce it in the same way as the stomach and the intestines are there to perform digestion, the liver to filter the bile, the parotid, maxillary and sublingual glands to prepare the salivary juice." This is the clear summons to a physiological psychology. Very naturally, Cabanis aimed to supply what Condillac omitted. Condillac's sensationalism, like that of the English school, found basis in the external senses. It therefore missed those organic and internal changes which physiology alone could set forth. Cabanis, accordingly, insisted that multitudes of impressions proceed continually from the internal organs to the brain, and that the conditions of the cerebro-spinal system form a determining factor in this process. Or, to be more emphatic, as it continues to maintain its unstable equilibrium, the organism originates vital feelings within itself—feelings that bear no direct reference to the external world. That is, the impressions of Locke and Hume do not play upon a tabula rasa, but are met, and twisted, by these organic feelings. The unconscious joins up with the conscious. Of this process instinct offers a conspicuous example, Here, primordial experiences, traceable to the embryo, provide a foundation of organic sensation which (in the light of the doctrine of evolution) would explain away psychological processes as automatic—as epiphenomena of the bodily substrate. In this respect Cabanis was a prophet. Nevertheless, despite his studies of age, sex, temperament, sensibility, irritability, habit, climate, the fœtus and instinct, he fails to work through his great theme with the necessary grasp upon detail. His epoch would not let him. Yet he saw the promised land afar off. For, to him, psychology was already a natural science. It traffics with phenomena, never with metaphysical realities, and its material must be found in the relation of mental states to physiological conditions. Hampered everywhere by contemporary ignorance of nervous anatomy, he still contrived to formulate a vivid and convincing psycho-physiological schema, for which, we may as well confess, due praise has never reached him. Physiology passed to another land, and he fell into an oblivion rather discreditable to the historical insight of those who came to elaborate his anticipations.

Plainly a physiological psychology can not emerge in absence of a