828 THE POPULAR SCIENCE MONTHLY. 



Biichner, in his recently published and translated work on " Mind 

 in Animals," gives a singular observation analogous to the above, 

 which was communicated to him by Herr G. Theuerkauf. A maple- 

 tree standing in the grounds of Herr Vollbaum, of Elbing, swarmed 

 with ants and aphides. In order to check the mischief, the proprietor 

 smeared about a foot width of the ground around the tree with tar. 

 The first ants that arrived stuck fast ; but the next, seeing the pre- 

 dicament of their companions, turned back and fetched a number of 

 aphides from the tree, which they stuck down on the tar one after 

 another till they had made a bridge over which they could cross with- 

 out danger. 



It will be observed that all these cases, being so analogous although 

 recorded independently by different observers, serve to corroborate 

 one another. As such corroboration in matters of this kind is of 

 value, I shall here add two or three cases which go to confirm the 

 observation of Cardinal Fleury regarding the construction of a float- 

 ing bridge. Dr. Ellendorf writes to Professor Buchner that he pro- 

 tected a cupboard of his provisions from the invasion of ants by 

 standing the legs of the cupboard in saucers filled with water. He 

 adds : 



I mvself did this, bntlnone the less found thousands of ants in the cupboard 

 next morning. It was a puzzle to me how they crossed the water, but the puzzle 

 was soon solved. For I found a straw in one of the saucers. . . . This they had 

 used as a bridge. ... I pushed the straw about an inch from the cupboard-leg, 

 when a terrible coufasion arose. In a moment the leg immediately over the 

 water was covered with hundreds of ants feeling for the bridge in every direc- 

 tion with their antennae, running back again and coming in ever larger swarms, 

 as though they had communicated to their companions within the cupboard the 

 fearful misfortune that had taken place. Meanwhile the new-comers continued 

 to run along tlie straw, and, not finding the leg of the cupboard, the greatest per- 

 plexity arose. They hurried along the edge of the saucer, and soon found where 

 the fault lay. With united forces they pulled and pushed at the straw, until it 

 again came into contact with the wood, and the communication was again 

 restored. 



The military ants, both in America and Africa, exhibit still more 

 extraordinary resources in the way of bridge-making. Thus Belt says 

 of the Ecitons : 



I once saw a wide column trying to pass along a crumbling, nearly perpen- 

 dicular, slope. They would have got very slowly over it, and many of them 

 would have fallen ; but a number having secured their hold, and reaching to 

 each other, remained stationary, and over them the main column passed. An- 

 other time they were crossing a water-course along a small branch, not thicker 

 than a goose-quill. They widened this natural bridge to three times its width 

 by a number of ants clinging to it and to each other on each side, over which 

 the column passed three or four deep ; whereas, excepting for this expedient, 

 they would have had to pass over in single file, and treble the time would have 

 been consumed. 



