INTELLIGENCE OF ANTS. 827 



McCook's account whether he himself witnessed the facts. The facts, 

 however, which he narrates, are that a peach-tree having grown up so 

 as to overshadow a nest of harvesting ants, the latter climbed the tree 

 to strip off the leaves. " I am convinced," says McCook, " that the 

 reason for this onsla\ight was the desire to be rid of the obnoxious 

 shade." If this statement had been met with in any ordinary book on 

 animal intelligence, of course I should not have quoted it ; but as 

 McCook went to Texas for the express purpose of studying these ants 

 in a scientific manner, and as the numerous other observations which 

 he made, both on these and on the mound-building species, entitle him 

 to respect, I have not felt justified in suppressing this statement. 



The observation made by Colonel Sykes on certain ants in India 

 has gained a wide notoriety from its having been published by Spence 

 in his popular work on instinct. Colonel Sykes was a good observer, 

 so that his account ought not to be questioned. He says that in order 

 to guard his provisions from the ants he put them on a table, the four 

 legs of which he placed in as many basins filled with water. Some 

 ants still succeeded in scrambling across the water, and so the legs of 

 the table were likewise painted with turpentine. The ants then ran 

 up a wall near which the table stood, and when about a foot above its 

 level, they sprang from the wall to the table. 



Somewhat analogous to this is the observation of Professor Leuck- 

 hart, who placed round the trunk of a tree, which had been visited by 

 ants as a pasture for aphides, a broad cloth soaked in tobacco-water. 

 When the ants, returning home dowTi the trunk of the tree, arrived at 

 the soaked cloth, they turned round, went up the tree again to some 

 of the overhanging branches, and allowed themselves to drop clear of 

 the obnoxious barrier. On the other hand, the ants which desired to 

 mount the tree first examined the nature of the obstruction, then 

 turned back and procured some pellets of earth, which they carried in 

 their jaws and deposited, one after another, upon the cloth till a harm- 

 less road of earth was made across it. 



This observation of Professor Leuckhart is in turn a corroboration 

 of an almost identical one made more than a century ago by Cardinal 

 Fleury, and communicated by him to Reaumur, who published it in 

 his " Natural History of Insects " (1734). The Cardinal smeared the 

 trunk of a tree with bird-lime, in order to prevent the ants from 

 ascending it ; but the insects overcame the obstacle by making a road 

 of earth, small stones, etc., as in the case just mentioned. On another 

 occasion the Cardinal saw a number of ants make a bridge across a 

 vessel of water surrounding the bottom of an orange-tree tub. They 

 did so by conveying a number of little pieces of wood, the choice of 

 that material, instead of earth or stones, as in the previous case, ap- 

 parently betokening no small knowledge of practical engineering 

 a knowledge which, as we shall presently see, is also shared by the 

 Ecitons. 



