But no general law, no systematic connection can be deduced from such relative proportions. They serve only to demonstrate a characteristic.
Upon this characteristic depends preeminently the beauty of the human visage. If we are considering the visage from its æsthetic aspect and wish to compare it with the muzzle of animals, we may say that in regard to its proportions it is as though the muzzle had been forced backward from its apex, while the cranium had swelled, through the increase of its vertical diameter. The muzzle is formed of the two jaws alone, on the upper of which the nose is located horizontally; there is neither forehead nor chin along the vertical line of the visage. As the jaws recede and the cranium augments, the forehead rises, the nose becomes vertical, and when the mandible has retreated beyond the frontal limit, the wide yawning mouth has been reduced in size, while a new formation has appeared below it—the chin. By this, I am trying merely to draw a comparison which I trust will be of service by suggesting a didactic method of illustrating the reduction of an animal's muzzle to human proportions. Whatever forms a part of the visage bears the morphological stamp of humanity: the forehead, the erect nose and the entire region of the mandible, which contains the principal beauty of the human face.
The narrow opening of the lips, mobile because so richly endowed with the muscles that unite in forming it, is quite truly the charming and gracious doorway of the organs of speech, which by shaping the internal thought into words are able to give it utterance; while the winning smile allures, captivates and consoles, thereby accomplishing an eminently social function; and sociability is inseparable from humanity.
The animal mouth, on the contrary, is the organ for seizing food, the organ of mastication, and, in felines, a weapon of offence and a means of destruction.
Tarde says: "The mandibles seem to shape themselves in accordance to the degree of intelligence; they become more finely modeled in proportion as the two social functions of speaking and smiling acquire a greater importance than the two individual functions of biting and masticating."
And Mantegazza says: "Cruelty has localised its imprint around the mouth, perhaps because killing and eating are two successive moments of the same event."
The Normal Visage
The visage is that part of the body which is preeminently human; being richly endowed with muscles, it represents the "mirror of the soul," through the expressions that it assumes according to the successive sentiments, passions and transitions of thought. The visage is a true mine of individual characteristics, by which different persons may be most easily and clearly distinguished from one another; while at the same time it bears the stamp of the most general characteristics of race, such as the form, the expression, the tone of complexion, etc., in consequence of which the face has hitherto held the first place in the classifications of the human races.