124 ANIMAL INTELLIGENCE. 



the larvae at A. When the ants had made a number of 

 jom*neys over c D A and back again, he raised the block c D 

 so that there was an interval —q of an inch between the 

 end of the block D and the larvae at a. 



The ants kept on coming, and tried hard to reach down 

 from D to A, which was only just out of their reach. . . . After 

 a while they all gave up their efforts and went away, 

 losing their prize in spite of most earnest efforts, because it 

 did not occur to them to drop -^^ of an inch. At the mo- 

 ment when the separation was made there were fifteen ants on 

 the larvae. These could, of course, have returned if one had 

 stood still and allowed the others to get on its back. This, 

 however, did not occur to them ; nor did they think of letting 

 themselves drop from the bottom of the paper (p) on to the 

 nest. Two or three, indeed, fell down, I have no doubt by 

 accident ; but the remainder wandered about, until at length 

 most of them got into the water. 



In another experiment he interposed a light straw 

 bridge on the way between the nest and the larvae, and 

 when the ants had well learnt the way, he drew the 

 bridge a short distance towards the nest, so that a small 

 chasm was made in the road. The ants tried hard and 

 ineffectually to reach across it, but it did not occur to 

 them to push the straw into its original position. 



The following experiment is still more illustrative of 

 the absence of intelligence, because the adjustive action 

 required would not demand the exercise of such high 

 powers of imagination and abstraction as would have been 

 required for the moving forwards of the paper drawbridge : 



To test their intelligence I made the following experiments : 

 I suspended some honey over a nest of Lasius Jlavus at a 

 height of about -J an inch, and accessible only by a paper bridge 

 more than 10 feet long. Under the glass I then placed a 

 small heap of earth. The ants soon swarmed over the earth 

 on to the glass, and began feeding on the honey. I then re- 

 moved a little of the earth, so that there was an interval of 

 about ^ of an inch between the glass and the earth; but, 

 though the distance was so small, they would not jump down, 

 but preferred to go round by the long bridge. They tried in 

 vain to stretch up from the earth to the glass, which, however, 

 was just out of their reach, though they could touch it with 



