AN ESSAY ON PHYSIOLOGICAL PSYCHOLOGY. BY ROBERT DUNN, F.R.C.S. ENG. FELLOW OF THE ROYAL MEDICAL AND CHIRURGICAL SOCIETY, OF THE MEDICAL ETC. ETC. LONDON: JOHN CHURCHILL, NEW BURLINGTON STREET. 1858. LONDON: SAVILL AND EDWARDS, PRINTERS, CHANDOS STREET, COVENT GARDEN. BOSTON MEDICAL LIBRARY IN THE FRANCIS A. COUNTWAY ΤΟ DR. WILLIAM B. CARPENTER, F.R.S. ETC. ETC. MY DEAR SIR,—Impressed with the conviction that to you, more than to any other physiologist or metaphysician of the age, belongs the honour of having placed the great doctrines of Mind on the solid basis of a sound Physiological Psychology, I have much pleasure in dedicating to you the attempt made in the following Essay to expound some physiological points in connexion with our mental constitution, which you were among the first to enunciate; and, at the same time, in having such an opportunity as this presents, not merely for recording my sense of the value of your psychological labours, but of acknowledging the advantages and the pleasure which I have derived from your private friendship and social intercourse. That you, my dear Sir, may long be spared to your family and to science, is the ardent hope and fervent wish of yours sincerely, 31, NORFOLK STREET, April 1, 1858. ROBERT DUNN. PREFATORY NOTICE. THE following chapters on Physiological Psychology have appeared as a series of Papers in the "Journal of Psychological Medicine and Mental Pathology," edited by Forbes Winslow, M.D., D.C.L. Written at varying intervals amid the distractions of medical practice, I am sensibly aware that they bear too evident marks of needless repetitions, and of a want of unity in the treatment of the subject; and yet these were perhaps in a measure unavoidable, under the circumstances of their composition. There is reason, however, to believe that these papers have proved a stimulus to thought, and have roused into activity the energy of other minds of high endowments, possessing more leisure and better opportunities than I can command for successfully prosecuting such an interesting inquiry; and this belief has led to their republication in a separate form. Of the importance of the subject, and of its practical bearings upon Psychological Medicine, there can be no dispute, for surely it is on Mental Physiology, and a knowledge of the Correlations of Physiology and Psychology, that a rational and enlightened practice can alone be based. Besides and physiologically or psychologically considered, self-knowledge is equally important. R. D. PHYSIOLOGICAL PSYCHOLOGY. CHAPTER I. Genesis of the Mind.-Consciousness, an ultimate Fact; a succession of States.-Self-Consciousness, the Primary Condition of Intelligence. - Phenomena and Nervous Apparatus of the Sensational Consciousness. It is no longer a subject of dispute, that the doctrines of mind rest essentially on the basis of our physiological compositionthat they form a part of the physiology of man. For, however it may be attempted to separate intellectual and moral from animal and corporeal man, and however we may reason about our intellectual and moral nature apart from our bodily and animal constitution, it is never to be forgotten that they are united in this life, forming one and a composite system of mutual dependence and reciprocal action. From the first moment that the primitive cell-germ of an human organism comes into being, and is launched upon the ocean of time and space, it may literally be said, that the entire individual is present, that an organized entity exists, fitted for a human destiny; and that, from the same moment, matter and mind, body and soul, are never for an instant separated. Their union constitutes the essential mode of our present existence, and they are alike subject to the laws of development and growth; for the mind, like the body, passes through its phases of development. Not only is the framework and different organs of the human body evolved and perfected, one after the other, in accordance with all the subsequent wants of the future man; but, among the rest, and from the same primitive cell-germ, are gradually developed, the nervous apparatus and the encephalic ganglia, upon the vesicular matter of which the mind is dependent for the manifestation of all its activities. And thus we see, that in the primitive cell |