In _Yetta Ségal_,[65] a slender thread of a story is used by Mr. _Rollin_ as the vehicle for a theory of "type fusion" or convergence which he thinks has not received sufficient attention from social or scientific students. There are a pair of lovers, one of whom is discovered at a critical period in the courtship to have negro blood in his veins, and a philosopher who comes forward to satisfy the parties (who hardly need it) that this is no serious matter, but is all according to human evolution and the destiny of the race. "You must be impressed," he says, "by the fact that there are a great many people here and there, of mixed blood, and that the number is increasing; ... it is well that not a few are indeed truly admirable specimens of the human race. Such phenomena must be interpreted in a way consistent with man's nature: if he is developmental; if he shall attain a higher status through struggle, or through means that are seemingly, or for the time, degrading; if he is moving from the simple to the complex, as to organization; if universal movement tends to unific existence--then race interchange, with elimination of peculiar characteristics, has probably made its appearance as a phase of infinite order, and for the benefit of future man.... It is presumptuous for the wisest to assert that the man of lower type has no element of strength peculiar to his race which the most advanced does not need in his present organization. It may be needed either for present protection in the way of re-enforcement, or as an element of strength for further advancement." Mr. Rollin does not advocate type fusion or wish to accelerate the movement, but presents it as a fact and factor in human evolution deserving more extensive and thorough study than it has received.