532 
David H. Dolley 
is not in the comparatively scanty numbers of these cells observed. The 
niost positive indication of such significance for this type is the fact that 
examples of it have been found belonging to both the sensory and to 
the rnotor (as Fig. 24) groups. The interpretation must remain tentative 
until tested by experiment of overactivity with adequate time for re- 
cnperation. 
Deductions regarding the mechanics of nerve cell activity — the relation 
of the size changes to the formation of chromatin. 
This discussion will be made in terms of the idea as expressed by 
Richard Hertwig (1902) of the mutual interdependence and interchange 
of materials between the cell body and the nucleus as specifically re- 
lated to the formation of chromatin. More iiicidentaUy, as the main 
evidence rests upon the Purkinje cell elsewhere discussed fuUy, it will 
tend to substantiate as a natural coroUary the doctrine particularly ad- 
vocated by Richard Goldschmidt as to the existence in the cytoplasm 
of certain cells of a permanent though fluctuating supply of extra-nuclear, 
fiinctioning nuclear material. The discussion will bear particularly upon 
the former from the side of the further evidence from measurenients of the 
reciprocal action between the cell body and its nucleus. That the result- 
iiig product, the chromidial apparatus, is immediately derived through 
the mediation of the nucleus, this will furnish contributory though in- 
direct evidence. The intra- and extra-nuclear basic chromatic sub- 
stance of the primitive crayfish cells does not afford in any shifts in its 
local distribution objective evidence which directly admits of an inter- 
pretation of the nuclear origin of the extra-nuclear portion. In these 
cells, so far as activity has been camed, though it is to be noted that that 
is not to absolute exhaustion, the chromatin, excepting that belonging 
to the karyosome, is throughout localized in the cytoplasm and is not 
linked to the nucleus by any transitions of formed chromatin from one 
to the other, as in certain stages of activity of the Purkinje ceU. Out- 
side of the karyosome, no formed chromatin appeai’s within the nucleus, 
and the final Step, the disintegration of the karyosome, has not been 
observed. However, the Status of the nerve cell in possessing such an 
attribute in the so-called Nissl substance seems more firmly grounded 
than for any other cell. 
As the points of correspondence between the Nissl substance and 
chromidial apparatus have been taken up in previous papers and the 
literature cited, they need merely be summarized. 
