"Formica sanguinea, which may be assumed to have comparatively recently taken to slave-making, has not yet been materially affected.
"Polyergus, on the contrary, already illustrates the lowering tendency of slavery. They have lost their knowledge of art, their natural affection for their young, and even the instinct of feeding. They are, however, bold and powerful marauders.
"In Strongylognathus the enervating influence of slavery has gone further, and told even on the bodily strength. They are no longer able to capture their slaves in open warfare. Still they retain a semblance of authority, and, when aroused, will fight bravely, though in vain.
"In Anergates, finally, we come to the last scene of this sad history. We may safely conclude that in distant times their ancestors lived, as so many ants do now, partly by hunting, partly on honey; that by degrees they became bold marauders, and gradually took to keeping slaves; that for a time they maintained their strength and agility, though losing by degrees their real independence, their arts, and many of their instincts; that gradually even their bodily force dwindled away under the enervating influence to which they had subjected themselves, until they sank to their present degraded condition—weak in body and mind, few in numbers and apparently nearly extinct, the miserable representatives of far superior ancestors, maintaining a precarious existence as contemptible parasites of their former slaves."[80]
This is truly a wonderful picture of mental and physical degeneration incident to the enervating influences of slavery. That it is a true one, an abundance of data most emphatically declares. The influence of slavery on the human race (the masters) shows very plainly that man himself quickly, comparatively speaking, loses his stamina when subjected to it.
This fact is but another proof of the kinship of all animals, and the similarity, nay, the sameness, of mind in man and the lower animals; mind is the same in kind, though differing in degree.
When an animal is placed amid new and unfamiliar surroundings necessitating the evolvement of intelligent action in order to meet the necessities of such environment, such an animal evinces ratiocination. I have seen many instances of such action on the part of ants. The following data concerning the natural history of the honey-making ant (Myrmecocystus mexicanus) are taken from my note-book.
During the summer of 1887 I spent several weeks in New Mexico, and while there had the great good fortune to discover a colony of honey-making ants. I found these ants in a little valley debouching out of Huerfanos Park, a government reservation, I believe, at that time. The nest was situated on the sandy shore of a small creek, and was a perfect square of three or four feet, from which all grass, weeds, etc., had been carefully removed. Around three sides of this square, viz., north, east, and west, a column of black soldier ants continually patrolled night and day.
Near the southeast corner of this open space the entrance to the nest was situated. The south side of the square was not guarded, but was left open for the entrance and exit of the hundreds of dark yellow workers which were engaged in bringing food to the village. No sooner was a burden put down than it was seized by black workers, which then carried it into the nest. At no time did I see a black worker bringing food to the centre of the square, nor did I ever see a yellow worker carrying food into the nest; the blacks and the yellows never interfered with one another's business.
To test the reasoning powers of these ants, I partially disabled a centipede and threw it into the square a short distance from the patrol line. For a moment or two the line was broken by the warriors hurrying out to do battle with the squirming intruder. But only for a moment or two, for orders were issued by some ant in authority (so it seemed, and so I believe), and the line was established, though somewhat thinned by the absence of soldiers. The messenger was sent to headquarters and reënforcements were sent out, and soon the line was as strong as ever, though hundreds of soldiers were warring with the centipede. The latter was soon killed, and its body was removed piecemeal by the yellow workers, which carried the fragments far beyond the boundaries of the square.