HEREDITY AND EVOLUTION 91 



minuter phases of likeness are reproduced, is certain, 

 even to the extent of reappearance of acquired 

 characteristics ; we seek therefore, if possible, to 

 ascertain how such minuteness of detail is secured. 

 Must we here be content to say with Darwin much 

 remains obscure, and will long remain obscure; or, 

 may we hope to press inquiry further, with reason 

 able expectation of some addition to our certainties ? 

 The theory of Evolution of organic life is deeply con 

 cerned in this problem as to transmission of acquired 

 characters. That strong testimony for Evolution is 

 supplied by rapid improvement in the breed of 

 animals under the care of the stock-farmer, is certain. 

 The facts are so suggestive as to press onwards this 

 course of observation. The problem for consideration 

 is the mode in which these germ or reproductive cells 

 become influenced, so that after being isolated from 

 the cells which make the bulk of the body of 

 the parent, they can transmit to the offspring the 

 characters of the parent organism/ l 



The conditions under which an answer to this 

 problem can be sought are such as to involve the 

 inquiry in great perplexity. The first thing essential 

 here is to keep fully in view the facts already 

 ascertained, having direct bearing on the problem. 

 As to cell life, we are assured that reproduction is 

 possible, in the first instance, apart from sexual 

 differences, by growth of the cell, involving expansion, 

 and multiplication, by severance of a young cell from 

 the parent cell, thus starting a distinct individual life 

 by division (parthenogenesis). Further, it seems clear 

 that the germ-cells after their isolation take no part 



1 Sir W. Turner s Address : Mature, p. 52&quot;. 



