44 David H. Dolley, 



The Distinction on Anatomical Grounds between Functional 

 Activity and Functional Depression. 

 By way of premise, then, for the conclusions which follow, sepa- 

 rate and distinct changes in form and structure underlie the physio- 

 logical conditions of activity and depression. The demonstration of 

 that cytologically, as presented elsewhere in numerous papers, will be 

 taken for granted. Richard Hertwig's nucleus-plasma relation theory 

 (1903), with its underlying idea of the reciprocal interchange of 

 materials, holds for the nerve cell. Excitatory stimulation in all its 

 mechanical, chemical, thermal, trophic and spontaneous forms sets in 

 motion an identical mechanism in all nerve cells. Constant and pre- 

 cise shifts of mass take place as a result of the absorption, elabora- 

 tion, interchange and consumption of materials. The evidence supports 

 the view of Hertwig, stated in 1902, as to the origin of chromatin. 

 According to this view, the cytoplasm contributes pro-chromatic 

 materials to the nucleus; through its nucleolar substance, the nucleus 

 synthesizes these into chromatin; from the nucleus, chromatin as such 

 or in modified form is returned to the cytoplasm. The chief though 

 not necessarily the sole final synthetic product of the mechanism for 

 the nerve cell throughout the ontogenetic and phylogenetic scale is 

 in the opinion of the writer the chemical range of the chromatin 

 substances. The extra-nuclear portion of these, which is functioning 

 nuclear material, chromidial apparatus in the sense of (xoldschmidt 

 (1904) for the purpose of active function, has been heretofore known 

 as the Nissl substance. Chromatin is the product of intracellular 

 coordination and the immediate source of the outward display of 

 energy. To its formation both the plasma and the nucleus contribute, 

 though it comes immediately to the cytoplasm by way of the nucleus. 

 Renewal of chromatin under continuous excitation depends on the 

 functional hypertrophy of the plasma and the nucleus — an invariable 

 combination. The cell comes to a point of exhaustion: chromatin 

 disappears not alone from the outside of the nucleus but from within 

 as well; the cell is dechromatinized; the nucleus-plasma balance is 

 disturbed in favor of the cytoplasm. Yet after due rest, the chromatin 

 all comes back, the cell is perfectly restored and ready to run its 



