No. 533] NUCLEUS AND CYTOPLASM IN HEREDITY 291 



same in all cases and that where it occurs among germ- 

 cells the mechanism is more carefully adjusted than 

 elsewhere. To quote his own words' regarding such 

 divisions in Leptinotarsa, "Thus in the oogonia and 

 spermatogonia, division of the nucleus is preceded by a 

 very exact division of a large chromatin nucleolus, and 

 as the halves separate surrounded by a clear area, the 

 appearance reminds one very much of the division of a 

 chromosome on a spindle.'' Other investigators of such 

 amitosis depict in their figures a mechanism which may 

 have the same significance. From preparations of my 

 own showing amitosis in the testes of snails and of 

 PI <nutria, a similar interpretation could be given. 



On this enzyme conception, however, constancy in 

 number is not the fundamental necessity. The require- 

 ment is really constancy of equilibrium between chromo- 

 somal constituents. It matters not whether this is 



maintained. The ultimate karyokinetic divisions of such 

 germ-cells as earlier divide amitotically would seem to 

 ho the restitution of such a balance so that the proper 

 quantitative conditions exist in the finished germ-cell. 

 Wieman would account for the appearance of amitosis 

 111 oarly germ-cells on the ground of a reduced oxygen 

 *"P}>ly in each individual cell, consequent upon a very 

 rapid increase in cell multiplication. All that is de- 

 K'ande.l in the onzvmic conception which I am present- 

 ing is the preservation in some way of the general fu- 

 sion of equilibrium so that each enzymic focus can 

 resume its customarv activities when the occasion de- 

 mands, or, to express it less teleologieally, when tic oc- 



This conception would seem all the more tenable since 

 we have had to discard the idea of the continuance of 

 actual chromosomal individuality in favor of that of 



