

PREFACE 





SHORTLY after the appearance of Dr. Oscar Hert- 

 wig's treatise ' Praformation oder Epigenese ?' I 

 published in Natural Science (1894) a detailed 

 abstract of it. But the momentous issues involved 

 in the problem of heredity, and the great interest 

 excited by Dr. Weismann's theories, make it de- 

 sirable that a full translation should appear. By 

 the kindness of Dr. Hertwig and his German pub- 

 lisher, this is now possible. I have prefixed an 

 introduction, written for those who are interested 

 in the general problem, but who have little acquaint- 

 ance with the technical matters on which the 

 argument turns. In the actual translation I have 

 tried no more than to give a faithful rendering of 

 the German. After no little perplexity, I have 

 rendered the German word Anlage as 'rudiment.' 

 It is true, a double meaning has been grafted upon 

 the English word, and it is widely employed to mean 

 an undeveloped structure, without discrimination 

 between incipient and vestigial character. I use it 

 in the etymological sense, as an incipient structure. 

 For the difficult words, Erbgleich and Erbungleich, 

 a succession of new terms have been suggested. 

 Here I use for the first term the word ' doubling,' 



for the second ' differentiating.' 



P. C. M. 



