Physiology of the nervous system / by J. P. Morat ; translated and edited by H. W. Syers.
- Jean-Pierre Morat
- Date:
- 1906
Licence: In copyright
Credit: Physiology of the nervous system / by J. P. Morat ; translated and edited by H. W. Syers. Source: Wellcome Collection.
694/716 (page 662)
![and innumerable modifications which take place in the course of all these actions. But we are far indeed from the attainment of such a result. Nevertheless, a start has been made as regards the performance of this analysis, in so far as portions of the brain which preside over certain functions or operations of the mind are differentiated. We already know that each specific sensation (each particular form of sensa- tion) is located in a special system which, were it entirely abolished, would cause all trace of the corresponding sensations to disa])pear, and at the same time would prevent all possibility of tlieir renewal. We also know tliat mutilation effected at the periphery of such a system, Ijy separating it from its normal stimulus, renders impossible that formation of physical images which is essential for the renewal of the sensation, but allows of the subsistence of tlie psychical images stored up in the memory. We also know that, conversely, tlie removal of determinate regions of the cortex, which are the culminating points of each of these systems—while permitting tlie renewal of the stimulus at the periphery, and also the persistence of certain reflex automatic or instinctive manifestations, of unconscious or subconscious nature, wJiich are united to the organization of the sub-cortical portion of the system—destroys the provision of coi'responding psychical images. Pathological dissociation of the elements of language.—But the visual, like the auditory, images are more or less complicated representations. Below the images properly so called, exist sensations, wliich are their elements. The images result- ing from their grouping are, some, concrete (images of objects), others, .symbolical or abstract (verbal images, or those of language whether spoken or written). Pathology demonstrates that some of these images may disappear, wliile others are preserved more or less unaltered. The disappearance thus effected may concern the sensations or images of a given sense, while allowing of the sub- sistence of those of other senses ; a choice may also be made between the more or less complicated orders of the different images or representations of this sense. It may, for example, suppress the verbal images of hearing or of vision, wliile allowing the images of objects to persist, and naturally also the sensations, in a more or less partial manner. It may suppress all the psychical images and only permit the sensations to remain ; and, finally, it may destroy the iisychical manifestations of a sense so utterly that nothing of it remains. Aphasia.—When the disturbance of which the brain is the seat is limited to the suppression of verbal images, aphasia ensues. The person suffering from aphasia is not also the victim of aphonia, for he preserves intact the motor powers of language, though he is incapable of using them. Neither is he to be considered as mentally affected, for he possesses ideas which he is incapable of expressing. A disturbance of this nature, which respects both the inferior sensori-motor activities and also to a certain extent the formation of ideas, is necessarily a local disturbance. It is indeed seated in the brain and, further, it only affects in this organ one of the systems participating in the function of language ; for, were it to involve all these systems simultaneously, it would not be the expression of the idea alone, which would disappear, but also the idea itself. As ideation has many sources (audition, vision . . .) and equally numerous means of expres- sion (speech, writing . . .), it persists, but in, it is true, a more or less shattered condition. A person suffering from aphasia is an individual who has not lost the whole function of language, but one of the factors taking part in this complex function. The lesion giving rise to aphasia presents distinct anatomical and functional forms. Sometimes it destroys, in the cortex itself, the partial systems which](https://iiif.wellcomecollection.org/image/b28716851_0694.jp2/full/800%2C/0/default.jpg)
