45 



This unexpected discovery of Beard's was but the fore- 

 runner of many others, for in quick succession following the 

 demonstration that the embryo was not the direct product of the 

 egg, it was demonstrated that germ-cells are not derived from 

 soma-cells; that there is a morphological continuity of germ- 

 cells from one generation to another ; that a law exists under- 

 lying the number of primary germ-cells ; that sex is determined 

 before the embryo commences its growth, and that it is there- 

 fore beyond the control of its environment ; that no such 

 process as that known as metamorphosis ever takes place. That 

 this so-called metamorphosis which professes to explain the 

 changes which take place during embryonic development, and 

 which endeavours to account for the changes by a process 

 known as a substitution of organs, is in fact a substitution of 

 organisms. 



Further as a result of Dr. Beard's work we may at once 

 put aside Darwin's provisional hypothesis of Pangenesis, 

 Galton's theory of Stirp, Spencer's theory of Physiological 

 units, Haeckel's Perigenesis of the Plastidule, de Vries's Pang- 

 enes, and Weismann's Continuity of Germ-plasm, autl substitute 

 the (leDionstrated fact of the Contiiuiity of germ-cells from one 

 generation to another, and therewith accept the solution of the 

 problem of heredity. It includes also the demonstration of the 

 source of like-twins ; throws new light upon the problems 

 involved in parthenogenesis ; and explains the course of 

 oogenesis and spermatogenesis in hermaphroditism. Further as 

 a result of his work it may be assumed that the probability of 

 Epigenesis is reduced to at best a mere possibility. 



It may in brief be stated that Beard's discoveries will 

 prove to be as revolutionary to biology as was the teaching of 

 Darwin fifty years ago. 



Now, what evidence does Dr. Beard offer in proof of the 

 results just set forth ? 



Beard's published work on germ-cells refers chiefly to his 

 researches in the embryogeny of the smooth skate (Raja 



