CHAPTER XVII. Psychology and Pathology of Memory. Ir is difficult to suggest a physiological or metaphysical hypothesis which satisfactorily explains those remarkable conditions of mental paralysis, singular manifestations and aberrations of memory (to which I have previously referred), as preceding, accompanying, and following acute and chronic affections of the brain, unless we espouse the doctrine of the indestructibility of ideas, and subscribe to the notion that no impression made upon the mind is ever destroyed. If we accept this as an established philosophical theory, we can easily understand how subtle microscopic changes in the delicate nerve vesicle (grey matter of the brain), may cause great eccentricity and singular irregularity in the exercise of the memory, and occasionally, in certain morbid as well as healthy conditions of cerebral exaltation, awaken into active consciousness, ideas imagined either to have no existence, or long since posed to be buried in oblivion.* sup Annihilation exists but in the fancy. It is an illusion of the imagination, a dream of the poet, the wild and * Is the permanent character of the pictures traced upon the memory dependent (as Locke surmises) on the "temper" of the brain, as if some impressions were made upon marble, others on freestone, and some on little better than on sand? "Cur seniores amplius mente valeamus, juniores citius discimus ?" asks Aristotle; why is it that in youth we learn more quickly, and wherefore is it, as age advances, the intellect becomes more powerful ? > frigid phantasy of the sceptic. Nothing obvious to sense admits of destruction. This is a well-established axiom in physics. It is not in the power of man to destroy the slightest particle of matter. What is termed "destruction," as applied to material substances, is nothing but a change in their elementary composition, or alteration of their constituent atoms. The good and wise Benefactor, the Beneficent Creator of the universe, has not delegated to poor puny man the power of destroying any portion of the physical universe by which he is surrounded, and which ministers so bountifully and mercifully to his every necessity. He may, by chemical or other scientific processes, alter and re-arrange the existing combinations of organic matter, but, when disintegrated by such means, the particles so dissipated and apparently destroyed, enter into new and different forms, and assume other types and organisms, but are, in their original nature and elements, never annihilated. What is true with regard to material, holds good, à fortiori, respecting psychical phenomena. Hence the tonic, permanent and indestructible character of the impressions made upon the cerebrum, and received and registered in the mind during infancy and childhood, as well as in adult age, as established by their resuscitation in advanced and at other periods of life during certain normal and abnormal conditions of the vesicular brain structure, and cerebral circulation.* * I use the phrase "received" advisedly, for it must be admitted that there are many impressions which impinge themselves transiently on the mind-ideas that are evanescent in their character, and therefore obtain no settled hold upon the consciousness-which cannot philosophically be deemed as received and registered in the memorial archives. Such are the fugitive notions which do not become objects of perception, that so frequently float upon, and pass like shadows over the surface of the mind, in early as well as in matured life, when the brain is not anatomically and physiologically organized or fitted for the facile perception, reception, and registration of ideas. There can be no doubt that the defective memory which so often accompanies old age, is mainly dependent upon certain (as yet unexplaine) "The images," says an illustrious English moralist, "which memory presents are of a stubborn and untractable nature. The objects of remembrance have already existed, and left their signature behind them impressed upon the mind, so as to defy all attempts at erasure or of change. Whatever we have once deposited, as Dryden expresses it, in the sacred treasures of the past,' is out of the reach of accident or violence, nor can it be lost, either by our own weakness, or another's malice." "Non tamen irritum Quodcunque retro est efficiet; neque Quod fugiens semel hora vexit." Horace, lib. iii., ode 29. 'The seeds of immortal truth," remarks an eminent modifications in the physical nutrition or chemical constitution of the brain interfering with that vital, organic, and I may add psychical sensibility, so essentially necessary for its ready adaptation to mental impressions. It may be, that the ideas are in reality received, but that the faculty of reminis cence being either originally defective or enfeebled by age or disease, it ceases to obey the commands of the will. The atrophy, as well as diminution in the depth and complexity of the convoluted surface of the brain, so often witnessed after death, in aged persons, undoubtedly impairs that organic cerebral susceptibility and sensibility so necessary for the rapid and permanent reception of mental impressions. I had an opportunity, last year, of observing two remarkable illustrations of this fact. I was present at the post mortem examination of the body of a gentleman who died of visceral disease, at the advanced age of 84. Up to this period he had been remarkable for great vigour of intellect, and for extraordinary elasticity and retentiveness of memory. He appeared to have forgotten no impression that ever had been made upon his mind, in early as well as in advanced life. During the examination of the brain I was remarkably struck with its anatomical appearance. The grey matter was by no means diminished in quantity or consistence. The sulci were well marked, and both as to volume, character, and depth of its convolutions, the brain presented an aspect similar to what a pathologist would expect to detect in a person dying in full intellectual power at the age of 30 or 40. In another case, I examined the brain of a gentleman whose mind had become prematurely enfeebled for six years previously to his death. He died at the early age of 56. The convolutions of the brain had greatly diminished in depth as well as in complexity, and the encephalic mass also presented a general shrunken or atrophied appearance. The brain was unusually pale, and there was also (without softening) a want of coherence in its texture. *" The Rambler." Dr. Johnson. writer, are not sown to perish, even in the loose soil where they have long laid disregarded."* Goethe embodies the same idea in the following transcendently beautiful passage: "Kein Wesen kann zu nichts zerfallen, Das Ew'ge regt sich fort in allen, Am Seyn erhalte dich beglückt ! Das Seyn ist ewig, denn Gesetze Aus welchen sich das All geschmückt."† How, it may be asked, can the physiologist and pathologist reconcile with this latency and indestructibility of psychical conceptions, the fact of the constant wear and tear, destruction and construction, waste and reparation, absorption and deposition of nerve-brain-matter? Can the doctrine of the individuality and indivisibility of mind, and the metaphysical theory of the unity of the consciousness, be established on a philosophical basis, if these physical laws are acknowledged thus materially to alter the structural organization of the brain, and to produce modifications in its recognised intellectual and emotional manifestations? Is not the gradual development of the mind from childhood to adult age, and its steady and melancholy decadence from a condition of youthful vigour and advanced maturity, to that of second childhood, and senile imbecility, connected with those subtle changes in the composition of the cerebral matter and modifications in the organization of the grey nerve vesicle, which we know to be in constant progression? How can we explain the expansion and discipline which the mind undergoes as the effect of a system of educational training? By what physiological and psychical processes are the memory, attention, and reasoning * "Amenities of Literature," by Isaac Disraeli, vol. ii. p. 365. faculties, developed and invigorated by exercise? exercise? What is the rationale of the judgment being improved by judicious and careful cultivation, the moral sense elevated, the taste disciplined and chastened, the volitional power increased? Are not these various psychical changes the results of some new, and as yet inexplicable law regulating the action of nerve-matter? Is it possible to suppose that changes similar to those previously referred to, in the manifestations of the thinking principle, can be consequent upon any alteration in the mind per se? May not these developments and modifications in the psychical attributes of the cerebrum, and gradual unfoldings of the mind which we perceive through the various epochs of life, be mysteriously connected with and dependent upon, that waste and repair of nerve matter which all physiologists recognise to be in constant operation? Are these psychical phenomena more inexplicable and inscrutable to the philosopher than the physical facts that the physiologist is daily making matter of observation and reflection? How can we account for the transmission of particular types of disease, certain modifications. and eccentricities of physical organization from generation to generation? Are these phenomena less occult than the descent of mental idiosyncrasies, modulations of the voice and expressions of the countenance, from father to son, mother to daughter? Slight distortions in the feet, peculiar malformations in the fingers, singular defects in the development of the muscles regulating the movements of the eyes, moles, mother's marks, have all been known to be physical defects, or, more properly speaking, arrests of structural development, that have existed in families for generations! How can we reconcile these physical facts with our notions of the organic revolutions occurring in the animal economy? Again, if we turn to the consideration of pathological phenomena, the physiologist is still more bewildered in |