6. It is evident what great profit accrues from this arrangement whereby a general instinct like imitation takes the place of a number of special instincts, or supplements them. It gives a measure of plasticity to the creature. He can now respond suitably to changes in the environment in which he lives. The special instincts, on the contrary, are for the most part so fixed that the animal must act just as they require him to in this or that circumstance; but as soon as his instinct takes on the form of imitation, the resulting action tends to conform itself to the model actions of the other creatures which set "copies" before him. These more or less new results due to recent research in the province of Instinct have had direct bearing upon theories of the origin of instinct and of its place in animal life. _Theories of Instinct._--Apart from the older view which saw in animal instinct simply a matter of original created endowment, whereby each animal was made once for all "after his kind," and according to which there is no further reason that the instincts are what they are than that they were made so; apart from this "special creation" view, two different ideas have had currency, both based upon the theory of evolution. Each of these views assumes that the instincts have been developed from more simple animal actions by a gradual process; but they differ as to the elements originally entering into the actions which afterward became instinctive. 1. First, there is what is called the Reflex Theory. This holds that instincts are reflex actions, like the closing of the eye when an object threatens to enter it, only much more complex. They are due to the compounding and adding together of simple reflexes, in greater and greater number, and with increasing efficiency. This theory attempts to account for instinct entirely in terms of nervous action. It goes with that view of evolution which holds that the nervous system has had its growth from generation to generation by the continued reflex adjustments of the organism to its environment, whereby more and more delicate adaptations to the external world were secured. In this way, say the advocates of this theory, we may account for the fact that the animal has no adequate knowledge of what he is doing when he performs an act instinctively; he has no end or aim in his mind; he simply feels his nervous system doing what it is fitted to do by its organic adaptations to the stimulations of air, and earth, and sea, whatever these may be. But it may be asked: Why do succeeding generations improve each on its parents, so that there is a gradual tendency to perfect the instinct?