THE SEAT OF FORMATIVE AND REGENERATIVE 
ENERGY. 
Cc. O. WHITMAN. 
THE question as to the role of the cytoplasm, presents itself 
under two forms: 
1. Is the cytoplasm a passive body, moving only as it is acted 
upon by external forces, or in response to influences emanating 
from the nucleus? 
2. Or does it behave rather like an organized body, endowed 
with subtle powers of its own, and capable of automatic as well 
as responsive action ? 
There is a strong tendency at the present time to refer all 
kinetic changes in the cytoplasm to the agency of the nucleus, 
and to ascribe to the former the passive role of a nutritive sub- 
stance. The kinetic phenomena of the egg during maturation 
and impregnation have already been considered in their bearing 
on this important question.!. A number of decisive proofs of 
pure nuclear action were pointed out, and at the same time an 
attempt was made to support the opinion that the cytoplasm is 
capable of automatic as well as responsive action. The present 
paper is chiefly devoted to the consideration of phenomena dis- 
played in the cytoplasm, and to the discussion of the question, 
whether the regenerative and formative power of the cell resides 
in the nucleus or in the cytoplasm, or in both taken as a highly 
complex physiological unit. 
The Doctrine of Isotropy. — Pfliiger’s interesting experiments ? 
with the amphibian egg to determine the influence of gravitation 
upon the direction of cleavage-planes, led him to conclude that 
the entire egg is “zsotropic.” In other words, to quote from the 
1O6kinesis. Yourn. Morph., 1., 2, p. 227, December, 1887. 
2 Ueber den Einfluss der Schwerkraft auf die Theilung der Zellen. Arch. f. d. ges. 
Physiologie, XXXI., pp. 311-318, and XXXII, pp. 1-79. 1883. 
