I t will naturally be understood that the narrowing of the subject to a relatively small field of Animal Psychology compels the author to use only a very small number out of the many hundreds of facts and observations on the intel lectual life of animals, which have been sent to him from all parts of the world in answer to his public request, and for which he here again returns his public acknowledgment; further, the greater number of these communications give the result, as might be expected, of daily and private observa tions on the more accessible animals. The author therefore ventures to refer his respected correspondents to a later work from his own pen which, as compared with the present book, undertakes a far wider task. He will therein endeavor, by means of a psychological classification, to trace the dif forent affections and manifestations of man's emotional and intellectual life throughout the great circles of the animal world. Here also most of the communications will be found under the names of the several observers, and the author trusts that this will be accepted as his personal acknowledg ment for individual help.