No. 533] NUCLEUS AND CYTOPLASM IN HEREDITY 305 



I do not wish to be understood as maintaining that the 

 nucleus or the chromosomes have no other than enzymic 

 functions. We know that the nucleus contains highly 

 complex proteins and it would seem improbable that all 

 of them are concerned exclusively with matters of fer- 

 mentation. There is some evidence, however, that the 

 ferments themselves may be of the nature of nucleo- 

 proteids. If this is true it is possible that under certain 

 conditions they operate as ferments and under other con- 

 ditions as building or other necessary materials. My 

 chief desire has been, without entering into a discussion 

 of the manifold functions the nucleus may perform, to 

 point out one obviously necessary function, the control 

 of velocities in cell chemistry, that is explicable on the 

 basis of enzymic activities, and to bring forward reasons 

 for inferring that these have their sources in the chromo- 



In conclusion, then, recalling the fact of the inconceiv- 

 able number of stereoisomers that the proteid molecule 

 may possess, and the fact that to make up protoplasm 

 diverse proteins, at least, and various enzymes probably 

 themselves of proteid nature, are required, we would 

 seem to possess in the chemistry of relatively known 

 chemical substances in nucleus and cytoplasm an ade- 

 quate basis for interpreting the mechanism of heredity 

 without resorting to other more hypothetical entities. 



Before we embrace out of the void such new phantoms 

 as "psychoids" or "entelechies" is it not incumbent 

 upon us to strive still further to expand our knowledge of 

 protein constitution and configuration? In the mean- 

 time it would seem best to look upon the organism, 

 whether germ-cell or adult, as but the expression of an 

 extended cycle of processes which are due to the intrinsic 

 properties of the chemical constituents of protoplasm. 

 Sueh an attitude at least has the merit of keeping within 

 nailing distance of tangible facts and processes. 



