730 JOHN BEARD, 



Indeed, grantrng the right to explain away the awkward facts of 

 certain of the above cases — and it would not be according to the 

 methods of strict scientific investigation to do this — there exist far 

 more instances, where it is clear as the light of day, that sex is not 

 determined or influenced by fertilisation, where it is beyond any pos- 

 sible doubt an attribute, a function, of the egg itself. 



Were it possible to furnish proof of a convincing character of the 

 determination of sex in any particular direction, male or female, by 

 the spermatozoon in any single instance, the facts concerning the 

 twofold sexually differentiated gametes, the eggs, of certain females, 

 and those relating to the two categories of spermatozoa i), would be 

 meaningless and useless. But with these very facts all the phenomena 

 of sexual reproduction in the Metazoa can be shown to be in harmony. 



With the supposed occult influence of the spermatozoon mystery 

 and metaphysics are introduced, where simplicity rules. By rejecting 

 the existence of this power a road leading to error is for ever closed. 

 And by accepting the plain and obvious facts concerning the fourfold 

 gametes of the Metazoa a step is taken along the pathway of truth. 



IV. The Manifestation of Sex. 

 There has been at least one attempt to base the "origin of binary 

 sex" in the former existence of three sorts of gametes, termed by 

 Hartog micro-, meso-, and mega -gametes (M. M. Hartog, Some 

 problems of reproduction, in: Quart. J. microsc. Sc, 1891, p. 72). 

 The identity in number is, however, the sole resemblance between 

 Hartog's theory of the "origin of sex" and the account of the 

 determination of sex, given here. Moreover, Hartog makes the meso- 

 gametes disappear as useless 2) organisms, and thus he reduces the 

 actual number to two, which is not in accordance with the facts. Nor 

 is any attempt made to show how the differentiation is carried on 

 from generation to generation. It has been indicated here how the 

 male- eggs as a rule only provide for a male embryo and its set of 

 male gametes, the spermatozoa : whereas the female-eggs make provision 



1) With very few' exceptions, and of these Ascaris megalocephala 

 and Salamandra maculosa may be named, there is hardly a dioecious 

 animal yet investigated, of which it can with certainty be said, that a 

 second form of sperm is completely absent. In the two apparent ones 

 mentioned the very numerous degenerative spermatogonia and spermato- 

 cytes suffice to account for the missing second non-functional sperm. 



2) He writes "less useful" (op. cit. p. 72). 



