THE LA WS OF SPEECH. 195 



which, broadly regarded, is not necessarily associated with speech. The 

 savage in his contact with the civilised man, or one civilised man in 

 his relations with his equals, may employ the language of gesture, 

 and be perfectly understood, as one may daily prove by crossing the 

 English Channel and watching our unsophisticated neighbours in their 

 converse with the foreigner. In lower life, there is abundant evidence 

 that communication of a very distinct kind by means of signs or acts 

 is a common practice. Some species of ants, for instance, keep the 

 aphides, or plant-lice, of our gardens in their nests much as we keep 

 cows in dairies, or seek the plant-lice in their native haunts on the 

 bushes and flowers, where, to the gardener's disgust, they exist by the 

 score. Approaching its aphis-cow, the ant proceeds to milk it by 

 stroking the tail of the insect with its antennae or feelers. Thereupon 

 the " cow " emits a drop of a sweet secretion which the ant greedily 

 drinks, and then hurries off in search of a fresh subject. There has 

 evidently been induced arid perfected in this case a close relationship 

 between ants and aphides ; since we note that the latter are pro- 

 tected in many ways by the ants, and exhibit a perfect docility of 

 demeanour under the treatment to which they are subjected by these 

 impersonations of insect wisdom. 



One species of ant (Lasins flavus\ indeed, is known to live 

 chiefly upon the honey of the plant-lice which feed upon the roots 

 of grasses. In this instance, the plant-lice are kept in the ants' 

 nest, their very eggs being tended by the ants with an evident desire 

 of securing future favours ; " an act," says Sir John Lubbock, 

 "which one is much tempted to refer to forethought, and which in 

 such a case implies a degree of prudence superior to that of some 

 savages." But that the mere touch of the ants' antennae possesses 

 all the significance of a sign-language is evident from the spontaneous 

 response which the plant-lice make to' the stimulus, and likewise 

 from tlie impossibility of imitating the ant's procedure. Mr. Darwin 

 tells us that on one occasion he "removed all the ants from a 

 group of about a dozen aphides on a dock-plant, and prevented their 

 attendance during several hours. After this interval I felt sure," 

 continues Mr. Darwin, "that the aphides would want to excrete. I 

 watched them for some time through a lens, but not one excreted ; 

 I then tickled and stroked them with a hair in the same manner, as 

 well as I could, as the ants do with their antennae ; but not one 

 excreted. Afterwards I allowed an ant to visit them, and it imme- 

 diately seemed by its eager way of running about to be well aware 

 what a rich flock it had discovered ; it then began to play with its 

 antennae on the abdomen first of one aphis and then of another ; and 

 each, as soon as it felt the antennae, immediately lifted up its abdomen 

 and excreted a limpid drop of sweet juice, which was eagerly devoured 

 by the ant. Even the quite young aphides," adds Mr. Darwin, 



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