ANTS— MEMORY. 41 



SO considerable a distance, this hypothesis does not 

 seem probable, and the only other one open to us is that 

 the ants remembered the site of their former home for a 

 period of twelve months. And this conclusion is rendered 

 less improbable from a statement of Karl Vogt in his 

 * Thierstaaten,' to the effect that for several successive 

 years ants from a certain nest used to go through certain 

 inhabited streets to a chemist's shop 600 metres distant, 

 in order to obtain access to a vessel filled with syrup. As 

 it cannot be supposed that this vessel was found in suc- 

 cessive working seasons by as many successive accidents, 

 it can only be concluded that the ants remembered the 

 syrup store from season to season. 



I shall now pass on to consider a class of highly re- 

 markable facts, perhaps the most remarkable of the many 

 remarkable facts connected with ant psychology. 



It has been known since the observations of Huber 

 that all the ants of the same nest or community recognise 

 one another as friends, while an ant introduced from 

 another nest, even though it be an ant of the same 

 species, is known at once to be a foreigner, and is usually 

 maltreated or put to death. Huber found that when he 

 removed an ant from a nest and kept it away from its 

 companions for a period of four months it was still recog- 

 nised as a friend, and caressed by its previous fellow- 

 citizens after the manner in which ants show friendship, 

 viz., by stroking antennae. Sir John Lubbock, after re- 

 peating and fully confirming these observations, extended 

 them as follows. He first tried keeping the separated ant 

 away from the nest for a still longer period than four 

 months, and found that even after a separation of more 

 than a year the animal was recognised as before. He re- 

 peated this experiment a number of times, and always 

 with the same invariable difference between the recep- 

 tion accorded to a foreigner and a native — no matter, 

 apparently, how long the native had been absent. 



Considering the enormous number of ants that go to- 

 make a nest, it seems astonishing enough that they should 

 be all personally known to one another, and still more 

 astonishing that they should be able to recognise members 



