No. 605] 



NUCLEUS AND CYTOPLASM 



299 



ment can not take place. The investigation of the finer 

 physiological reactions which take place between the 

 nncleus and cytoplasm is badly needed, and th(^ restate- 

 ment of them in terms of physics and chemist Sncii 

 evidence as is available indicates that the importaiKu' of 

 the cytoplasm is, in the main, subordinate to that of the 

 nucleus. 



The evidence from egg-characters, it might be noted in 

 conclusion, is one-sided. 1 have no doubt that if sperm- 

 characters were to lie studied as intensively as egg-char- 

 acters have been (wliich has not been the case due to the 

 microscopic size of most sperins) the differential char- 

 acters in tlie sperm would lie found to behave in heredity 

 like tlie di tTer(>nlial cliaracters of eggs, and would be de- 

 termincil a> lai uclx- l>y the egg nucleus as by the nucleus 

 of the s|i(M-iii (.f liif in'cceding generation. 



Direct coiuimiily of snhstanccs in the cytoplasm is not 

 a method of hei-eility. It simply provides for the autono- 

 mous proliferation of materials with no determinative 

 significance. Xo coniproniise. tlien, is possil)le between 

 the two views outliiUMl ' N'\to])lasmic" and "cliromo- 

 M>me" theories of !(Mvdil>. The lir-^t i^ non determi- 

 native: the so.mmkI i. the pi-lniarily olTcctiv,^ method of 

 heiv.lity and of devel.MMnenl. The workin- of the ef- 



erly only com'eni.Mi with tlie way in" whi<'h the lieivditary 

 factors are distrihute.l in the -enn cells. Kor d.'veloi)- 

 ment, its meclianisni i< hnt u'l'ossly known, hnt W(> have 

 learned enouuh of the detei minative effect of the nucleu- 



nnd of the po.Hhilitie^ for MlterMction helueen cXtop'M^n 



niid nnclrn^ !<, foMer a ^i^pichm that oiio daN tiie ^nx 

 *M-M;ine(. ,,f the chronu.M.iHe^ ox ,t dex el.>]nnent ^^u\ he rx 

 plained in physical-chemical tcM-nis. 



BTBLTOORAPIIY 

 Cameron anrl Gladstone. imr>. Jo>ir». Anat. <nu1 Fhjmol., 

 Castle, W. E. 1010. Joudi. Frp. Znol . Vol. S, No. 2. 



