THE 



AMERICAN NATURALIST 



Vol. LI. December, 1917 No. 612 



THE GENESIS OF THE OKGANIZATION OF THE 

 INSECT EGG. II 



PROFESSOR liM)15EKT W. IIEGNER, 

 Zoological Labokatohv, rMvuisnv or Michigan 



5. Interaction of X nch niijiisi,} nnd C//foplasm 

 There are phenonieim tlint occur dininu- tlie growth 

 period that suggest liow iiia-x's of ('yto]>I;isin that are 

 differentiated hoth iiior])hologiea]ly and ])liysiologically 

 may aiise in tlie cortical layer of the insect egg. It lias 

 been suggested tliat ''most of the differentiations of tlie 

 egg cytoplasm have arisen during the ovarian history of 

 the egg and as a result of the interaction of nucleus and 

 cytoplasm; . . and with this we fully agree, but our 

 problem is to determine the nature of this interaction and 

 in what ways it may take place. 



During every mitosis there is a more or less thorough 

 mixing that involves the chromatin as well as other nuclear 

 constituents, since chromatin-diminution is a normal his- 

 tological process. Interchanges bctwot'ii niick'iis nnd 

 cytoplasm, therefore, occur during tlic two iiuiltipiicntion 

 ])eriods that precede the formation of oocytes. Abun- 

 dant opportunity is tlms offered for factor> in the cltrotiKt 

 somes to exei't an iiitluence iii»oii tlir* cell a> a whole. A 

 similar and proliablx' even greater dix-harge of chromatic 



