K was a box arranged so that three separate acts were required to open the door, which was held by two bolts at the top and two bars outside. One of the bolts was connected with a platform in the back center of the box so that depressing the platform raised the bolt. The other was raised by a string which ran up over a pulley in the front, across the box 1 inch above the bars, over a pulley near the corner of the box, and down to the floor, where it was fastened. Pulling on this string, either by clawing at it where it was running vertically from the last pulley to the floor, or by putting the paw out between the bars which covered the top of the box, and clawing the string downward, would raise the bolt. If both bolts were raised and _either_ bar was pushed up or down far enough to be out of the way, the cat could escape. K, or ‘_Triple_,’ as it may be called, is the box reproduced in Figure 1. L was a box that also required three acts to open the door. It was a combination of A (O at front), D (string), I (lever). The lever or bar to be depressed was 2 inches to the right of the door, which was in the front center. The string to be clawed or bitten ran from front center to back center 1 inch below the top of the box. Z was a box with back and sides entirely closed, with front and top closed by bars and screening, with a small opening in the left-hand corner. A box was held in front of this and drawn away when the cats happened to lick themselves. Thus escape and food followed always upon the impulse to lick themselves, and they soon would immediately start doing so as soon as pushed into the box. The same box was used with the impulse changed to that for scratching themselves. The size of this box was 15 × 10 × 16. EXPERIMENTS WITH CATS In these various boxes were put cats from among the following. I give approximately their ages while under experiment. No. 1. 8-10 months. No. 2. 5-7 months. No. 3. 5-11 months. No. 4. 5-8 months. No. 5. 5-7 months. No. 6. 3-5 months. No. 7. 3-5 months. No. 8. 6-6½ months. No. 10. 4-8 months. No. 11. 7-8 months. No. 12. 4-6 months. No. 13. 18-19 months.