66 THE AMEBIC AN NATURALIST [Vol. XLVI 



nuclear organization as have here been indicated are both 

 vague and artificial. Vague and crude they undoubtedly 

 are; and so they will remain until we have far more 

 thoroughly explored a field of inquiry in which we must 

 for the present make a shift with crude ideas unless we 

 are content to work with no ideas at all. They may be 

 artificial too ; but it appears to me that in this respect 

 they differ only in degree from the graphic formulas of 

 structural chemistry. The chemist does not hesitate to 

 picture definite topographical or spatial relations in the 

 complex organic molecule — symmetrical and asymmetrical 

 forms, cyclic or ring-formations, linear series, side- 

 chains and other such graphic constructions. It is by 

 their use that the whole science of organic chemistry has 

 been built up, and that such men as Emil Fischer and 

 Kossel have made nearly all of their advances in our 

 knowledge of those most complex of known organic com- 

 pounds the proteins. And these constructions are re- 

 garded by eminent investigators as something more than 

 mere figurative expressions or symbols. They are taken 

 more literally as representations or models — rude, no 

 doubt, but as far as they go real — of the actual arrange- 

 ments in space of the various molecular groups or pro- 

 tein "Bausteine." If therefore observation and experi- 

 ment lead the cytologist to postulate definite topograph- 

 ical relations among the nuclear substances, and if such 

 a conception help him to explain the results of genetic 

 studies, he finds himself in good company, even though 

 his present clumsy notions regarding the nuclear organi- 

 zation can as yet make no approach to the exact and ele- 

 gant constructions of the chemist. 



The essential conclusion that is indicated by cytolog- 

 ical study of the nuclear substance is that it is an aggre- 

 gate of many different chemical components, which do 

 not constitute a mere mechanical mixture, but a complex 

 organic system, and which undergo perfectly ordered 

 processes of segregation and distribution in the cycle of 

 cell-life. That these substances play some definite role 



