Sensory Discrimination : the Chemical Sense 89 



in the life of ants. In the first place, he demonstrated that it 

 is by chemical stimulation that ants are able to follow each tf 

 other to supplies of food; or to larvae, for an ant's behavior to 

 an ant larva found in the course of its wandering is like its 

 behavior to food; the larva is picked up and carried to the 

 nest. Lubbock put some larvae on a glass plate at a little 

 distance from one of his artificial ant nests, and set a similar 

 empty plate beside it; he then made a bridge of a strip of 

 paper leading from the nest toward the plates, and connected 

 each of them with this bridge by a separate short paper strip. 

 He placed a marked ant at the larvae ; she picked up one and 

 returned to the nest. She soon appeared followed by several 

 others ; when she had reached the larvae, and before the others 

 had arrived at the dividing of the ways, Lubbock exchanged 

 the short strips, so that the one over which the marked ant 

 had passed now led to the empty plate. The following ants 

 all took this path, indicating that they were guided by some 

 trace which her footsteps had left. Lubbock was inclined 

 to think, however, that some kind of communication must 

 have passed between the marked ant and her fellows in the 

 nest to induce them to follow her, and also that this communi- 

 cation might on occasion convey some notion of the quantity 

 of food or larvae to be had. He placed three glass plates near 

 an ant nest, connecting each of them with the nest by means 

 of a paper strip. On one plate he put a heap of several hun- 

 dred larvae, on the second two or three only; the third was 

 empty. He put marked ants on each of the plates, and cap- 

 tured all the ants which they led back with them. Many 

 more ants came to the plate with the larger heap of larvae 

 than to the others. Lubbock explained this by supposing 

 that the ant from that dish had in some way communicated 

 to the nest the greater numbers at her disposal (248, pp. 

 172 ff.). Obviously it would be enough to suppose that the 



