instances of intelligence of, [51-63];
ideas of causality in, [58-60];
appreciation of principles by, [60], [61];
sign-making by, [88-102];
understanding of words by, [123-127];
articulation by, [128-138], [152];
reasons why none have become intellectual rivals of man, [154-157];
self-consciousness in relation to, [175-178];
recognizing pictorial representations, [188], [189];
conditions to genesis of self-consciousness manifested by, [195-199];