mere complication of structure producing" consciousness is "out of the question." "Because man's physical structure has been developed from an animal form by natural selection, it does not follow that his mental nature, even though developed _pari passu_ with it, has been developed by the same causes only."[32] Yet, in assuming Weismann's theory, Wallace asserts: "Whatever other causes have been at work, Natural Selection is supreme, to an extent which even Darwin himself hesitated to claim for it." "While admitting, as Darwin always admitted, the cooeperation of the fundamental laws of growth and variation, of correlation and heredity, in determining the direction of lines of variation, or in the initiation of peculiar organs, we find that variation and natural selection are ever-present agencies which take possession, as it were, of every minute change originated by these fundamental causes, check or favor their further development, or modify them in countless ways according to the varying needs of the organism."[33] In the opening portions of this book Wallace introduces a teleological argument to the effect that the pain which we ordinarily conceive as connected with the struggle for existence among lower species is mostly a figment of our imagination. Periods of suffering are comparatively short, since death speedily and without anticipation puts an end to those animals in any way incapacitated. Livingstone describes how, when seized by a lion, a sort of stupor succeeded the first shock, so that he felt neither fear nor pain; it is probable that terror induces this same condition in animals seized by beasts of prey, and that their end is therefore painless after the first shock. Cold is generally severest at night and tends to produce sleep and painless extinction. Hunger is scarcely felt during periods of excitement, "and when food is scarce, the excitement of seeking it is at its greatest." Nor is the gradual exhaustion and weakness of slow starvation necessarily painful. FOOTNOTES: