Thus the sight of an external symbol, a banner, a standard, a flag, is capable of suddenly exciting in those who behold and salute it, the most diverse sentiments, from the fact that its appearance awakes in them a series of individual reminiscences. It is by the sight of the external pomp that surrounds them, the display of gold and silver embroideries, of brilliant uniforms, that the possessors of authority at all times and in all places have sought to inspire respect in the crowds before which they have passed. It is by securing the passive admiration of the eyes of their dazzled contemporaries that they have always main tained their prestige. It is for the gratification of the eye that human beings over the whole surface of the globe seek, according to their means, to ornament their persons and appear to the utmost advantage externally.
It is by the lust of the eye that we are all, small or great, young or old, rustics or citizens, captivated and allured ; for it is always our eyes that are first charmed by the contemplation of physical beauty; and the most powerful of sentiments, love, destined to set the heart of man beating, has, as a general rule, its sole origin in the seduction of the sight, the pleasure of the eyes, which ardently desire the object 'which has charmed them, and excited the spontaneous awaking of all latent delights.
It is, moreover, by means of those mysterious links which associate optic impressions with our sentiments, that our former emotions, our secret affections are awakened and maintained by the sight of certain keepsakes. Every one knows what a sweet consola tion for the absent are the features of a beloved person reproduced by painting ; how certain institutions, cer tain public or private ceremonies recurring in a periodic manner, certain anniversaries, are similarly calculated to revive in us former emotions, and again bring us into the presence of the persons and circumstances that have first inspired them, recalling the periods at which our emotions have been set in movement.
3. Again, in the sphere of purely intellectual pheno mena, optic impressions play a very important part which deserves attention.
Th is, either alone or associated with their excito motor fellows, which regulate without our know ledge the different movements of accommodation of the eye, they permit us to judge of the distance, the dimensions, and the forms of different surrounding objects. Thus, as when we have to do with the impres
sions of sensibility proper, former impressions are associated with recent, to form the elements of com parison. When we say that a body is at such or such a distance from us, there is a reflex action of the intelligence which, from our knowledge of the object, and the manner in which it is illuminated, associates a series of notions previously acquired with a recent impression. When, as regards a body that moves trans versely before us, we judge of the direction of this movement, it is still the evocation of an impression formerly received that comes to be annexed to a recent impression.
Thus by degrees a crowd of complex notions is created in the mind by the arrival of optic impressions, and their preservation in the state of persistent memories. The sense of sight consequently becomes one of the most fertile sources from which all our cere bral activity is incessantly fed. It is optic impressions again that with their acoustic fellows are called on to play such an important part in the artificial culture of the mind, both in the mental interpretation of graphic signs in the action of writing from dictation, and in the regular tracing of such characters in the action of writing spontaneously. They are also the introducers of the thoughts of others into our minds, when, with cur eyes fixed on the written characters, we attach to each of these characters correlative ideas and co-ordi.. nated emotions. They thus animate these silent cha racters, giving them life and fixing them in us as mate rials designed to excite in the mind new associations of ideas, and the most varied impressions.
They are therefore, in fact, the most powerful agents that stimulate the culture of the psycho-intellectual sphere, and fertilize its activity. They permit us at once to receive impressions from the thoughts of others, by means of written words, transmitted to a distance, and reciprocally to manifest our emotions and ideas in a manuscript_ form, which thus becomes the manifest expression of the different states that they pass through.
4. The important part that optic impressions play in the functionment-of mental activity leads to the con clusion that when they are wanting there will be a certain disturbance of the general equilibrium, which will have as its consequence special disturbances of cerebral functionment.