Page:Popular Science Monthly Volume 72.djvu/275

 difficulties, or, if we still designate their action in this way, the interpretation of "reflex" must be profoundly altered. Throughout the animal series improvement in the reaction to environment seems to signify greater nervous flexibility in dealing with experience rather than a complete change of method. In their fascinating paper on the habits of solitary wasps, the Peckhams tell of one who in filling up her nest "put her head down into it and bit away the loose earth from the sides, letting it fall to the bottom of the burrow, and then, after a quantity had accumulated, jammed it down with her head. She then brought earth from the outside and passed it in, afterwards biting more from the sides. When, at last, the filling was level with the ground, she brought a quantity of fine grains of dirt to the spot and, picking up a small pebble with her mandibles, used it as a hammer, pounding them down with rapid strokes, thus making this spot as hard and firm as the surrounding surface." Soon "she had dropped her stone and was bringing more earth," when she again picked up the pebble and pounded that which was brought until all was hard.

The power to inhibit, so that the same action does not always follow the same stimulus under the same circumstances, which was observed in Necturus, indicates, perhaps, the first break in the mechanism of primitive instincts. The part that experience plays in the animal's life is becoming more immediate and direct. Just how much consciousness is involved in this, or, indeed, whether there is any, we do not know. Investigation has shown that in man consciousness of means is not essential to the utilization of experience and there is certainly no reason for thinking it more necessary to the lower animals.

In the variability of instinct, also, we find mechanical organization less domineering, and in the study of wasps, to which we have just referred, the one preeminent, unmistakable and ever-present fact is variability. "Variability in every particular—in the shape of the nest and the manner of digging it, in the condition of the nest (whether closed or open) when left temporarily, in the method of stinging their prey, in the degree of malaxation, in the manner of carrying the victim, in the way of closing the nest, and last, and most important of all, in the condition produced in the victims of the stinging," some of them dying "long before the larva is ready to begin on them, while others live long past the time at which they would have been attacked and destroyed" had not the investigation "interfered

Ref 11 ''Loc. cit''., p. 30. is found on the following page.