Page:Popular Science Monthly Volume 31.djvu/173

Rh life, as unautomatic and ununiform in its outward aspect, as human life has ever been claimed to be.

In this article and a later one, I will run over the human instincts in detail, commenting with fullness only upon such as are interesting enough to repay the pains.

The line to be drawn between simply reflex and instinctive actions is an entirely arbitrary one; so I can see no objection, on the score of principle, to including under the title of instincts Professor Preyer's whole list of the gradually evolving propensities to action of the human babe: Sucking, biting, spitting, making grimaces, clasping, pointing, making sounds expressive of desire, carrying objects to the mouth, averting head and body, sitting up, standing, are all accomplishments which come in due order, and lead us to the locomotor age. Each is irresistibly called forth by some appropriate stimulus, and finally becomes subject to the conscious will.

Locomotion is more interesting. Until the walking impulse ripens in the nerve-centers, the legs remain limp and indifferent, no matter how often the child may be hung with his feet in contact with the ground. No sooner, however, has the standing instinct come, than the child stiffens his legs and presses downward as soon as his feet feel the floor. In some babies this is the earliest locomotor reaction. In others it is preceded by the impulse to creep. Yesterday, the baby sat contentedly wherever he was put. To-day, it is impossible to keep him sitting at all, so irresistible is his impulse to throw himself forward on his hands. Usually the arms are too weak, and the ambitious little experimenter falls on his nose. But his perseverance is dauntless, and he soon learns to travel in the quadrupedal way. The walking instinct may awaken with no less suddenness, and its entire education be completed within a week's compass, barring a little "grogginess" in the gait. The common belief that a baby learns to walk is, strictly speaking, untrue. The reflex machinery, as it begins to ripen, prompts him to its use. But, as it is imperfectly organized, he makes mistakes. If, however, a baby could be prevented from getting on his feet at all for a fortnight or so after his first impulse to do so had manifested itself, and then restored to freedom, I have little doubt of his then being able to walk perfectly, or almost perfectly, "from the word 'go.'" A small blister on each foot-sole would do the business; and it is much to be desired that some scientific widower, left alone with his infant at the critical moment, should repeat on the human species the brilliant observation of Mr. Douglas Spalding on various small birds, which he kept till they were fully fledged, and then found to fly with absolute perfection the first time he allowed them to spread their wings. Usually, birds start to fly before either the central or peripheral apparatus is quite ripe. And so do we, to walk.

Of vocalization I will say nothing except that it is instinctive in both of its forms, singing and speech, and that the propensity to speak