50 L. W. SACKETT 



When the forms were arranged so that the top edges were sim- 

 ilar, neither had. any difficulty. When arranged so that they 

 were similar on the left and at the same time individually sym- 

 metrical at top and bottom there was another shake-up in the 

 discriminative ability as the tables indicate. When this was 

 reversed and the forms were arranged similarly at the right, 

 No. 7 was still undisturbed but No. 6 made four errors in the 

 first five tests and then six errors in the next 50 tests. Before 

 discussing those results further it should be added that imme- 

 diately after these tests the six regular forms were newly painted, 

 and, after three days for No. 7 and 10 days for No. 6, these 

 animals were again tested. No. 7 selected the circle 18 times 

 in the first series and No. 6, 19 times. The "failures" were not 

 so much errors as irregularities. 



Four and one-half months later No. 7 was again tested with 

 the apparatus bearing the regular forms six- wise. In the first 

 series he made 11 right choices. The second series only 8 

 right choices with indications in general behavior, that the 

 association was disintegrating. He was then given the circle 

 and triangle pair-wise. The first series was perfect. The next 

 series with the circle and square was equally good. This was 

 followed by a mixed series in which the triangle, ellipse, hex- 

 agon, square and rectangle were paired successively with the 

 circle in the- order named, making each form appear four times 

 in the series. Only one error was made and that was what 

 appeared to be an inattentive plunge into the square. In the 

 six-wise tests which followed, the experimenter retired from the 

 room each time while the animal was making his reaction. His 

 results or behavior did not seem to be altered by this absence. 

 His right choices in a series were as follows: 7, 9, 13, 14, 15, 

 15, 13, 16. This experiment was not carried to completion but 

 it is evident that he was making good progress. 



And now it may be well to pause and ask what is the meaning 

 of these results on form discrimination. There is little doubt 

 that the sense of smell has been eliminated, both as a means 

 of locating the food by the direction of the odor and as a means 

 of trailing into the proper form. With No. 3 it is not certain 

 that kinaesthetic sensations were eliminated; rather the indi- 

 cations are that dermal and kinaesthetic factors played the 

 largest part in what selections he made. The behavior of the 



