,^ E. L. THORNDIKE. 



SO between two bars, at a point about 15 inches high and 6 

 inches in from the right edge of the front. We may call M 



' Lever outside.'' 



N was a pen 5 X 3 feet made of wire netting 46 inches high. 

 The door, 31 x 20, was in the right half of the front. A string 

 from the bolt passed up over a pulley and back to the back 

 center, where it was fastened 33 inches above the floor. Biting 

 or pawing this string opened the door. 



O was like K, except that there was only one bar, that the 

 string ran inside the box, so that it was easily accessible, and 

 that the bolt raised in K by depression of the platform could be 

 raised in O (and was by the dog experimented on) by sticking 

 the muzzle out between two bars just above the bolt and by bit- 

 ing the string, at the same time jerking it upward. O was 30 

 X 20 X 25 in size. 



The box G was used for both dogs and cats, without any 

 variation save that for dogs the resistance of the door to pres- 

 sure outwards was doubled. 



In these boxes w^ere put in the course of the experiments 

 dog I (about 8 months old), and dogs 2 and 3, adults, all of 

 small size. 



A dog who, when hungry, is shut up in one of these boxes 

 is not nearly so vigorous in his struggles to get out as is the 

 young cat. And even after he has experienced the pleasure of 

 eating on escape many times he does not try to get out so hard 

 as a cat, young or old. He does try to a certain extent. He 

 paws or bites the bars or screening, and tries to squeeze out 

 in a tame sort of way. He gives up his attempts sooner than 

 the cat, if they prove unsuccessful. Furthermore his attention 

 is taken by the food, not the confinement. He wants to get 

 to the food, not out of the box. So, unlike the cat, he con- 

 fines his efforts to the front of the box. It was also a practical 

 necessity that the dogs should be kept from howling in the 

 evening, and for this reason I could not use as a motive the 

 utter hunger which the cats were made to suffer. In the morn- 

 ing, when the experiments were made, the dogs were surely 

 hungry, and no experiment is recorded in which the dog was 

 not in a state to be willing to make a great effort for a bit of 



