88 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



equal as to their prospectivity, and in which there are no 

 potential diversities or restrictions of any kind. 



So much for differences in the real material organisation 

 of the germ and their bearing on inequipotentialities of the 

 cleavage cells. 



The Intimate Stricture of Protoplasm : Further Remarks 



Where a typical half- or quarter -development from 

 isolated blastomeres happens to occur, we know already 

 that the impossibility of a regulation of the intimate polar- 

 bilateral structure may account for it. As this impossibility 

 of regulation probably rests on rather simple physical condi- 

 tions * it may properly be stated that equal distribution 

 of potencies is not wanting but is only overshadowed here. 

 In this respect there exists a logical difference of funda- 

 mental importance between those cases of so-called " partial * 

 or better, " fragmental " development of isolated blastomeres 

 in which a certain embryonic organ is wanting on account 

 of its specific morphogenetic material being absent, and 

 those cases in which the " fragmental ' embryo lacks 

 complete cc halves " or " quarters " with regard to general 

 symmetry on account of the symmetry of its intimate 

 structure being irregularly disturbed. This logical difference 

 has not always received the attention which it undoubtedly 

 deserves. Our hypothetical intimate structure in itself is, 

 of course, also a result of factors concerned in ovogenesis. 

 Only in one case do we actually know anything about its 



1 It seems that these physical conditions also besides the real specifica- 

 tions in the organisation of the egg may be different before and after 

 maturation or (in other cases) fertilisation. (See Driesch, Archivf. Entwicke- 

 lungsmechanik, 7, p. 98 ; and Brachet, ibid. 22, p. 325. ) 



