From his earliest days on this planet man has ever been conscious that he has been walking on dangerous ground; that he is far from being lord of all he surveys; that instead there are powers, apparently quite outside of himself or of his control, of which he need definitely be on his guard. Under certain circumstances they will work for him, aid him, make his life more secure; under others, they can and do bring about just the reverse. With the dawn of conscience, which latter in essence may be called the memory of burnt fingers and rapped knuckles, he became convinced that certain courses of action definitely did not pay; others did. Together with other forms of magic he speedily discovered — or thought that he did — that it paid very decidedly to give to these invisible but dreadfully real powers what they wanted. Thus he might very possibly escape their vengeance, might even gain their favor. Do ut des, perhaps even more frequently do ne des, became one of the earliest utterances of what anthropologists with marked charity have denominated homo sapiens. It would appear to me too obvious and well attested to require detailed proof that sacrifice was man's attempt to placate, avert the anger, satisfy, make friendly to him, powers which he might or might not know, but toward which he had come to have, by the only way in which he has ever learned anything, viz., experience, a very lively respect.