Page:Popular Science Monthly Volume 58.djvu/529

Rh desire for food is very irregular and hard to control as a motive in experimental work.

The method of experimentation was simple. A box three feet long, two feet wide and ten inches deep was divided into four portions by partitions, also ten inches deep, arranged as shown in Fig. 1. In each partition was a hole four inches long and two inches deep, just large enough to permit the turtle to pass through easily. The box is shown in ground plan by Fig. 1.

A is the space in which the animal was placed to start, the starting-point being marked by a dot (.). The corner marked nest contained a mass of damp grass and was darkened. When everything was ready for an experiment the animal was placed in A at the dot and allowed to wander about until it found the nest by passing through the openings marked 1, 2 and 3.

On July 20 the animal, a speckled turtle about four inches long which was found in Woods Holl, Mass., was placed in A for

the first time. After wandering about almost constantly for thirty-five minutes, it chanced to find the nest, into which it immediately crawled, there remaining until taken out for another experiment two hours later. The observations were made from one to two hours apart, in order to avoid fatiguing the animal, and also to leave it some inducement for seeking the nest, for if it were taken out each time as soon as it got back to the comfortable corner, the game would soon lose interest. The second time the nest was reached in fifteen minutes, with much less wandering. The time for the third trip was five minutes, and for the fourth, three minutes thirty seconds. During the first three trials the courses taken were so tortuous that it seemed foolish to try to record them. There was aimless wandering from point to point within each space, and from space to space. After the third trip the routes became much more direct, and accurate records of them were obtained. Fig. 2 gives the course taken in the fourth experiment. It is fairly direct, but shows that the animal lost its way in A and again in B; having passed through 2, it took the shortest path to the nest.