Inheritance Materials of Germ-Cells 69 



realm, chromatin is a physical basis of heredity to only a 

 limited extent and in a partial way but has this office widely 

 and positively fixed in the higher moiety, the moiety, that is, 

 in which bisexual propagation is fully established, what 

 other conclusion can be drawn consistently with the modes 

 of reasoning universally sanctioned by evolutionists, than 

 that the function of "carrying hereditary qualities" by the 

 chromosomes in higher organisms is a secondary or ac- 

 quired, or better a delegated or assigned function? Hered- 

 ity is far older, phylogenetically, and far broader tax- 

 onomically than is the chromatin mechanism by which it 

 now in part manifests itself. Under this interpretation the 

 acquisition by chromosomes of the function of carrying 

 heredity would belong to the same evolutional type as for 

 example the acquisition by certain cells of the function of 

 muscular contraction, or by certain other cells of con- 

 ducting nervous stimuli. The advantage and satisfaction 

 of a conception of the role of chromosomes in heredity 

 which ranges them naturally and easily with all other or- 

 gans and tissues of the plant and animal body will be 

 quickly seen by every one to whom the seemingly endless 

 chance of discovering new interrelationships and consis- 

 tencies in living nature is one of the most rewarding things 

 about biological investigation. 



While we are duly impressed with the importance of per- 

 ceiving that chromosomes fall into the great class of other 

 organs and tissues when considered from the standpoint 

 of phyletic differentiation of structure and function, we 

 should not fail to notice that within the class they hold on 

 a number of counts a very distinct place. Probably the 

 most distinctive of these counts, at any rate the one most 

 important for this discussion, is the fact that while the vast 

 majority of tissues, taking the term in its usual meaning, 

 stand at or near the termination of the ontogenic series 

 are, in other words, the final stage in the series the chro- 



