468 DAVID H. DOLLEY 



Nucleus 



Size: Relatively small to volume Relatively large to volume plasma. 



plasma. 



Structure: Vesicular, edematous. Dense, packed. 



Chromatin: Progressively diminishes Hyperchromatism stage for stage (in- 



(absorbed by plasma at expense of crease" at expense of plasma). 



nucleus). 



A decrease relative to the cytoplasmic Absolute increase over activity, rela- 



content. tive increase to its cytoplasm. 



Karyosome: Karyorrhexis and kary- Karyorrhexis and karyolysis without 



olysis with plasmic resorption. Kar- plasmic resorption. Karyorrhexis 



yolysis predominates. predominates. 



Nucleolar substance: Progressive dim- Increase relative to activity stage for 



inution. stage. 



Terminal relations 



Upset of the nucleus-plasma* relation Upset of nucleus-plasma relation in 

 in favor of plasma. favor of nucleus. 



Functional activity ends in nuclear exhaustion. The residual 

 chromatin and the nucleolar substance are used up. Its re- 

 covery therefore involves the necessarily slow resynthesis of 

 these substances. But as fast as the synthesis occurs the cyto- 

 plasm exacts its complementary share of chromatic substance, 

 resorbs it. It makes no difference to the essentials of the process 

 whether this resorbed chromatic substance, the Nissl substance, 

 be identical with nuclear chromatin or merely an allied derivative 

 (Dolley, '13 a, p. 532, '13 b, p. 106). The restoration of Nissl 

 substance, which progresses slowly, and the loss of water— shrink- 

 age to normal size — are the initial features of recovery. On 

 the contrary, the most conspicuous and prolonged feature is the 

 lagging of the nucleus, both in size and intranuclear chromatin. 

 Usually not until the cytoplasmic content is complete does the 

 residual chromatin cover the nucleolus to form a karyosome 

 (Dolley, '11). 



It will be clearer to examine the state of a depressed cell which 

 falls short of degenerative change before stating the morpho- 

 logical indications of recovery. The nucleus-plasma inter- 

 change is blocked. The breakdown of the reciprocal relation is 

 due to the cytoplasm. It fails to furnish proper materials to 

 the nucleus, the lack of synthesis being demonstrated by the 



