Page:Popular Science Monthly Volume 52.djvu/458

440 and the sand with which it was mixed, and swallowed it all, and then stuffed the shell itself into his mouth. This act was not instinctive. It was the work of pure reason. Evidently his race was not familiar with the use of eggs. Reason is an inefficient agent at first, a weak tool; but when it is trained it becomes an agent more valuable and more powerful than any instinct.

The monkey Jocko tried to eat the egg offered him in much the same way that Bob did, but, not liking the taste, he threw the whole thing away.

The low intelligence of the lower animals—as the fishes—may be at times worse than none at all. If mental development were a real advantage to fishes it would take place through natural selection. The fishes taken in a large pound net, as I have observed them in Lake Michigan, can not escape from it because they have not intelligence enough to find the opening through which they have entered. If, however, a loon enters the net, the fishes become frightened and "lose their heads." In this case they will sooner or later all escape, for they cease to hunt about ineffectively for an opening, but flee automatically in straight lines, and these straight lines will in time bring them to the open door of the net.

Wild animals learn to avoid poisonous plants by instinct. Those who have not an inherited dislike for these plants perish. When the animals are brought into contact with vegetation unknown to their ancestors, this instinct fails them. Hence arises in California the danger from "loco weeds," as certain species of wild vetches are called. These plants produce temporary or permanent insanity or paralysis of nerve centers. The native ponies avoid them, but imported animals do not, and often fall victims to their nerve-poisoning influence.

The confusion of highly perfected instinct with intellect is very common in popular science. The instinct grows weak and less accurate in its automatic obedience as the intellect becomes available in its place. Both intellect and instinct are outgrowths from the simple reflex response to external conditions. But the instinct insures a single definite response to the corresponding stimulus. The intellect has a choice of responses. In its lower stages it is vacillating and ineffective; but as its development goes on it becomes alert, and adequate to the varied conditions of life. It rises with the need for improvement. It will therefore become impossible for the complexity of life to outgrow the adequacy of man to adapt himself to its conditions.

Many animals currently believed to be of high intelligence are not so. The fur seal, just mentioned, for example, finds its way back from the long swim of two or three thousand miles through a foggy