of such resistance in reclaiming from his hunting party the dead body of a female monkey that one fully understands why “the witnesses of this extraordinary scene resolved never again to fire at one of the monkey race."(22) In some species several individuals will combine to overturn a stone in order to search for ants’ eggs under it.  The hamadryas not only post sentries, but have been seen making a chain for the transmission of the spoil to a safe place; and their courage is well known.  Brehm’s description of the regular fight which his caravan had to sustain before the hamadryas would let it resume its journey in the valley of the Mensa, in Abyssinia, has become classical.(23) The playfulness of the tailed apes and the mutual attachment which reigns in the families of chimpanzees also are familiar to the general reader.  And if we find among the highest apes two species, the orang-outan and the gorilla, which are not sociable, we must remember that both—­limited as they are to very small areas, the one in the heart of Africa, and the other in the two islands of Borneo and Sumatra have all the appearance of being the last remnants of formerly much more numerous species.  The gorilla at least seems to have been sociable in olden times, if the apes mentioned in the Periplus really were gorillas.

We thus see, even from the above brief review, that life in societies is no exception in the animal world; it is the rule, the law of Nature, and it reaches its fullest development with the higher vertebrates.  Those species which live solitary, or in small families only, are relatively few, and their numbers are limited.  Nay, it appears very probable that, apart from a few exceptions, those birds and mammals which are not gregarious now, were living in societies before man multiplied on the earth and waged a permanent war against them, or destroyed the sources from which they formerly derived food.  “On ne s’associe pas pour mourir,” was the sound remark of Espinas; and Houzeau, who knew the animal world of some parts of America when it was not yet affected by man, wrote to the same effect.

Association is found in the animal world at all degrees of evolution; and, according to the grand idea of Herbert Spencer, so brilliantly developed in Perrier’s Colonies Animales, colonies are at the very origin of evolution in the animal kingdom.  But, in proportion as we ascend the scale of evolution, we see association growing more and more conscious.  It loses its purely physical character, it ceases to be simply instinctive, it becomes reasoned.  With the higher vertebrates it is periodical, or is resorted to for the satisfaction of a given want—­ propagation of the species, migration, hunting, or mutual defence.  It even becomes occasional, when birds associate against a robber, or mammals combine, under the pressure of exceptional circumstances, to emigrate.  In this last case, it becomes a voluntary deviation from habitual moods of life.  The combination sometimes appears