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ried in by three ants, one of whom, however, did comparatively little. The other two were imprisoned, and then, but not till then, a fresh ant appeared on the scene. She carried in the food for a week, and then she being imprisoned, two others undertook the task." *

One consideration more bearing upon obtaining supplies deserves to be recorded as altogether singular. Some species of ants watch over a distinct order of insects, the aphides, which exude a sweet fluid, using them exactly as we do cows for obtaining supplies of milk. The ant comes up to the aphis, gently strokes it with her feelers, forthwith the aphis gives forth its supply of honey, which the ant drinks up and departs. The facts were observed by Pierre Huber, and verified by Mr. Darwin. This verification was so interesting, that I give the narrative in a slightly condensed form. Mr. Darwin says,—"I removed all the ants from a group of about a dozen aphides on a dock-plant, and prevented their attendance during several hours." Mr. Darwin tried in vain by stroking the aphides with a hair, in imitation of the play of the feelers of the ants, to induce them to give up the

Scientific Lectures, p. 136.

honey. "Afterwards," he says, "I allowed an ant to visit them, and it immediately 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." * So the ants have their "cows" and milk them.

To attempt any account of the ants of tropical countries, where ants are most numerous, swarming in the regions they inhabit, and marching in hosts, would occupy too much space. I give, therefore, only a single reference extracted from the testimony of Mr. Savage concerning the driver ant of Western Africa (Anomma Arcens), so called because of the success with which it drives every thing before it. Mr. Savage annoyed by the proximity of a large settlement, discovered its quarters in some decaying granite. Kindling a fire around it, he believed he had succeeded in disposing of that settlement. Two days after, he went back to the spot, and instead

Origin of Species 6th ed. p. 207,

of desolation and death, he found "a tree at a short distance, about eighteen inches in diameter, to the height of four feet from the ground, with the adjacent plants and earth perfectly black with them." The most striking thing, *_ however, was that the ants had made festoons from the lower branches to the ground, formed in the following manner, as witnessed by Mr. Savage: "ant after ant coming down from above, extending their long limbs, and opening wide their jaws, gradually lengthening out the living chain" until first it was swaying to and fro, and ultimately fastened to the ground, when "others were ascending and descending upon them, thus holding free and ready communication with the lower and upper portions of this dense mass." In this same manner these ants provide for the crossing of water when on the march. "They make a line or chain of one another, gradually extending themselves by numbers across till the opposite side is reached." * This is exactly similar to the manner in which some monkeys are known to construct a natural bridge, only that the monkeys have the ad

* Museum, cf Naiural History edited by Richardson, Dallas, Cobbold, Baird, and White, Toi. ii. p. 184.

vantage of greater size and muscular strength, as well as prehensile power by the use of their tails. With such characteristics as have been briefly described, there is little wonder that a high place in the scale of intelligence has been claimed for these small insects. Sir John Lubbock, who has so patiently conducted his observations as to their modes of life, has stated this in the following manner,—"The anthropoid apes no doubt approach more to man in bodily structure than do any other animals; but when we consider the habits of ants, their social organization, their large communities, elaborate habitations, their roadways, their possession of domestic animals, and even in some cases of slaves, it must be admitted that they have a fair claim to rank next to man in the scale of intelligence." * Whether, even with all this evidence, we may be able to rank the ants quite as high as Lubbock here suggests, may be open to question. There may, for example, be reasonable debate whether the dog does not present still higher signs of intelligence, but it says a great deal for the ants that debate in the case should be possible. A question of very great scientific im

SeierU. Lects. p. 68.

portance is here raised, affecting the whole scheme of interpretation applicable to animal life, as connected with development of brain.

Without attempting to enter upon the argument yet to be conducted through the wider relations concerned, it must be obvious that the facts bearing on insect life must erelong have a larger share than they have yet had in influencing our generalizations. By reference to these, it becomes apparent, that anatomical structure is not in itself an adequate guide in determining comparative importance on the scale of organic existence; and, what is still more startling, that even comparative brain structure can not be taken as the sole test of the measure of intelligence belonging to animals. The whole orders of ants, taken collectively, must be regarded as presenting quite exceptional difficulties, not only for a theory of evolution regarded as an all-embracing science of life; but also for that theory of intelligence which seeks to account for diversities of power by the comparative complexity of brain structure.

Passing from more detailed discussion, it is needful to observe how wide and valuable are the results of these researches concerning the

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