his important work on the subject, puts it that it is a primitive rule that people living together in one residence do not intermarry, and he gives many examples which certainly tend to prove his point. But what about the cases, few only, it is true, where the opposite rule applies, as, for instance, amongst the Chukekes mentioned by Nordenskiold? If these were studied I believe, they would by some special feature in their practices do much to explain their relationship to the opposite group of practices. They would explain how far changes in custom were changes due to social and economical development which might have taken place under any conditions as to race, or whether they were due to causes which were essentially bound up with race, such as, for instance, conquest and slavery. The change from exogamy to endogamy, from descent through females to descent through males, from marriage by capture to marriage by purchase, and other changes which are now clearly defined in the history of human progress, are changes due more to economical causes than we are inclined to admit. And, if this is so, they might happen, or have happened, with any people when the causes are in full operation.
But my point is that these contrasts in human sociology want to be examined one against the other, want to be set down and stamped once for all with the stamp of scientific research, and not to be brought up against us at all sorts of times and occasions when their relevancy is not always so apparent as is the object of some adverse critic, whom you cannot answer because to do so would necessitate the writing of a separate treatise on a side issue. And then, when this has been accomplished, we could estimate what, in the contrasts of human social forms and human thought, is due to sheer obstinacy—the taking up of a particular view because one class or one group of people take up another view. Somewhere in such an investigation would have to be considered the long-continued obstinacy with which mother-right has clung to the ideas