OF MEMORY.
THE manifestations of memory, looked at as we have just done, do not then present themselves merely as a collection of simple phenomena, nor as the direct resultant of the impression made upon the plexuses of the cortical substance by an external excitation. They consist in true physiological processes, which have an origin and a regular evolution throughout the nervous system. They demand the active participation of the cerebral cell ; and to be regularly executed they must obey certain organic necessities, and the inevitable con ditions of integrity and co-operation of the organs through which they effect their complete development.
When, therefore, any disturbance whatever occurs either in the essential vitality or in the constitution of the organic elements which they lay under contribution, the processes of memory are ipso facto disjointed, and that faculty is thus maimed in one or other of the operations that constitute it.
Thus there are circumstances in which that property which the nervous elements possess, of retaining a record of external excitations which have formerly impressed them, attains a condition of extreme and permanent exaltation. This vibratory phase of their existence perpetuates itself and becomes a species of unsubduable erethism.
All phyiologists, indeed, have recognized the impor tant part a sudden emotion, such as terror or the sight of an epileptic attack,* plays in the production of convul sive seizures ; and I have further pointed out that violent impressions may remain stereotyped in certain indi viduals attacked with general paralysis, and that the shock caused in the sensorium may be very vivid, since it is capable of manifesting itself for several consecutive months in a species of cataleptic condition, imprinted upon the countenance, and upon the attitudes of the body.t The symptoms presented by the automaton whOse in teresting case has been reported by Mesnet, come under this class of facts. There are in such cases persistent impressions, which have been formerly accumulated in the automatic sensorium, which continues to direct the excito-motor processes without participation of the con scious personality.
Van Swieten, who was seized with vomiting on coming upon the dead body of a dog which exhaled an insup portable stench, chanced upon the same spot some years afterwards. The memory of what he had ex perienced produced the same disgust and the same consequences / which regulate the manifestations of normal activity. There are latent and si!ent stimulations which, by reason of certain conditions which have presided over their impression upon the organism, remain more vivid than others, and which, by virtually becoming incessantly active stirnetli, produce a discharge of nervous force, either in the form of interrupted convulsive currents, in that of continuos motor currents (cataleptic con dition of the muscles), or in that of sympathetic reactions from the side of vegetative life (vomiting, etc.).
In other circumstances, we have no longer to deal with an isolated phenomenon, revealing itself by definite manifestations, and reflecting as before the deviations of a normal process regularly accomplished. We ob serve, in fact, manifestations of quite a different kind, which reveal themselves by a species of exaltation of the psycho-intellectual regions, which preserve and store up external impressions in a very vivid manner, and when the cerebral elements have risen above their usual pitch, manifest their new condition by an unexpected super activity quite contrary to the habits of cerebral life of the individual.
We see patients, indeed, gifted with very ordinary hi telligence, who, when in this phase of cerebral erethism, will improvise, make quotations, associate new ideas with extreme rapidity, say witty things and make puns— things they are quite incapable of doing when in their ordinary vital condition.
Michea cites the case of a young butcher whom he ob served in the Bicetre, and who, under the influence of an attack of mania, recited whole speeches from the Phedre of Racine. During an interval of calm, he said he had but once heard the tragedy in question, and that, spite of all his efforts, he could not recite a single verse.