ANTS— MEMORY. 39 



Powers of Memory, 



Little need here be said to prove that ants display 

 some powers of memory ; for many of the observations and 

 experiments already detailed constitute a sufficient demon- 

 stration of the statement that they do. Thus, for instance, 

 the general fact that whenever an ant finds her way to a 

 store of food or larvse, she will return to it again and again 

 in a more or less direct line from her nest, constitutes 

 ample proof that the ant remembers the way to the store. 

 It is of considerable interest, however, to note that the 

 nature of this insect-memory appears to be, as far as it 

 goes, precisely identical with that of memory in general. 

 Thus, a new fact becomes impressed upon their memory 

 by repetition, and the impression is liable to become 

 effaced by lapse of time. More evidence on both these 

 features of insect-memory will be adduced when we come 

 to treat of the intelligence of bees ; but meanwhile it is 

 enough to refer to the fact that in his experiments on 

 ants. Sir John Lubbock found it necessary to teach the 

 insects by a repetition of several lessons their way to 

 treasure, if that way was long or unusual. 



With regard to the duration of memory, it does not 

 appear that any experiments have been made ; but the 

 following observation by Mr. Belt on this point in the case 

 of the leaf-cutting ant may here be stated. In June 1859 

 he found his garden invaded by these ants, and following 

 up their paths he found their nest about a hundred yards 



read another paper before the Linnaean Society, which contains some 

 important additional matter concerning the sense of direction in 

 ants. It seems that in the experiment above described, the hat-box 

 was not provided with a cover or lid, i.e. was not a ' closed chamber,' 

 :and that Sir John now finds the ants to take their bearings from the 

 ■direction in which they observe the light to fall upon them. For in 

 the experiment with the uncovered hat-box, if the source of light 

 {candle) is moved round together with the rotating table which sup- 

 ports the box, the ants continue their way without making compen- 

 sating changes in their direction of advance. The same thing happens 

 if the hat-box is covered, so as to make of it a dark chamber. Direction 

 of light being the soiirce of their information that their ground is being 

 moved, we can understand why they do not know that it is being 

 moved when it is moved in the direction of their advance, as in the 

 experiment with the paper slip. 



