34 A Century of Science 



gression, a line of development which human ideas 

 and institutions have followed. But in the most 

 advanced societies we find numerous traces of such 

 states of things as now exist only among savage or 

 barbarous societies. Our own ancestors were once 

 polytheists, with plenty of traces of fetishism. 

 They were organized in clans, phratries, and tribes. 

 There was a time when they used none but stone 

 tools and weapons; when there was no private 

 property in land, and no political structure higher 

 than the tribe. Among the forefathers of the pre- 

 sent civilized inhabitants of Europe are unmistak- 

 able traces of human sacrifices, and of the reckon- 

 ing of kinship through the mother only. When 

 we have come to survey large groups of facts of 

 this sort, the conclusion is irresistibly driven home 

 to us that the more advanced societies have gone 

 through various stages now represented here and 

 there by less advanced societies ; that there is a 

 general path of social development, along which, 

 owing to special circumstances, some peoples have 

 advanced a great way, some a less way, some but 

 a very little way ; and that by studying existing 

 savages and barbarians we get a valuable clue to 

 the interpretation of prehistoric times. All these 

 things are to-day commonplaces among students 

 of history and archaeology ; sixty years ago they 



