708 JOHN BEARD, 



writer's miod during his attempts to unriddle the problem of the de- 

 termination of sex. 



Of the problems of sex three aspects stand contrasted: these are 

 the determination, the regulation in nature, and the origin. The first 

 two are considered in the following pages, of the third no absolutely 

 certain knowledge is possible. 



University of Edinburgh, June 1901. 



Introduction. 



In certain scenes of the cyclical drama of the germ-cells or sexual 

 cells — in the course of the actual continuity of germ-cells from gen- 

 eration to generation, recently written of by the writer ^) — what we 

 term sexual individuals, males, females, or hermaphrodites, play 

 certain rôles. It is to these and to the transformations, undergone 

 by the germ-cells in their bodies, that the phenomena we term "sex" 

 attach. 



To finish off the main outlines of the cycle of the germ-cells 

 from one generation to the next it has become necessary to inquire 

 into the nature and determination of sex, and to attempt a solution 

 from the morphological side. The writer was unaware, that the "sex- 

 problem" was of necessity part and parcel of the great question of 

 the developmental history of the germ- cells, until it forced itself into 

 notice in a curious way. No attempt would have been made to solve 

 the problem, had it not raised itself. For the past thirteen years the 

 writer has been content, to follow out the track, revealed little by 

 little by his researches into the nature and mode of Vertebrate de- 

 velopment, without ever suggesting extraneous questions. 



To go no further back than the last two centuries, these have 

 witnessed, according to some authorities, upwards of five hundred 

 theories of sex. More than half of these have already been termed 

 "groundless hypotheses", and to the rest the same epithet may now 

 be applied, for, so far as I have been able to find out, there is not 

 one of them based in facts of morphology. 



The account of sex to be here presented is a morphological one. 

 It has nothing whatever to do with physiology; still less has it, like 



1) Beard, J., The morphological continuity of the germ-cells in 

 Raja batis, in: Anat. Anz., V. 18„ 1900 p. 465—485. 



