CYTOCHEMICAL TESTS ON EMBRYOS 



331 



Histones, thymonucleic acid ^ 

 possibly ribonucleic acid A, 



SCHEMATIC REPRESENTATION OF 

 THE PASSAGE OF (RIBOS-) NUCLEIC 

 ACID FROM THE NUCLEOLUS TO- 

 WARD AND THROUGH THE NUCLEAR 

 MEMBRANE, TO APPEAR AS CYTO- 

 PLASMIC NUCLEIC ACID WHICH IS 

 SYNTHESIZED INTO CYTOPLASMIC 

 PROTEINS. (P). 



(Redrawn from Brachet after 

 Caspersson, Hyden) 



A - cytoplasmic (ribos-) nucleic acid 

 C - chromatin 

 N - nuclear membrane 

 P - synthesized cytoplasmic proteins 

 (from "A") 



(Nucleolus - solid black) 



Histones, (complex proteins 

 and ribonucleic acid) 



Thymonucleic acid, histones, 

 possibly complex proteins 



E - euchromctin 



H - heterochromatin 



N - nucleolus 



P - complex protein 



Histones, complex proteins 

 possibly thymonucleic acid 



SCHEMATIC (CHEMICAL) STRUCTURE OF THE 

 CHROMOSOME (Redrawn from Brachet after 

 Caspersson) 



Telophase 







Euchromatin 





Prophase 





Heterochromatin 



Nucleolus 



Ribonucleic Acid, Plus 

 Cytoplasm, Less Euchromatin 



SCHEMATIC REPRESENTATION OF THE CHANGES IN 

 THE NUCLEOPROTEINS DURING MITOSIS 

 (Redrawn from Brachet after Caspersson) 



