No. 466.] STUDIES ON PLANT CELL.—VIIL. 231 
5. THE BALANCE OF NUCLEAR AND CYTOPLASMIC ACTIVI- 
TIES IN THE PLANT CELL. 
Two regions of the cell are sharply distinguished from one 
another with respect to both morphology and physiology. They 
are the nucleus and the cytoplasm. The nucleus soon dies if 
isolated from cytoplasm and the latter, lacking a nucleus, cannot 
be kept alive indefinitely unless it be in organic connection with 
a nucleated mass of protoplasm. The necessary connection 
may be only through delicate strands, as was established by 
Townsend ('97), and also seems to be illustrated in the instances 
of intercellular protoplasm which Michniewicz (: 04) reports are 
connected by delicate fibrillee (plasmodesmen) with neighboring 
cells. Some very interesting adjustments of the nucleus and 
cytoplasm to one another have been reported in a series of 
investigations of Gerassimow beginning in 1890. His most 
recent papers of the past year (Gerassimow, :04a, :04b) pre- 
sent a general summary of his studies and constitute a very im- 
portant contribution to the subject. They will furnish much of 
the material for this discussion. 
Gerassimow has found that the cells of Spirogyra and other 
members of the Conjugales offer admirable material for the 
study of the relations between the nucleus and cytoplasm, and 
throw important light on the functions, physiological activities, 
and interdependence of both structures. By subjecting fila- 
ments of Spirogyra during cell division to a temperature of 
o° C. or treating them for a short time to the anesthetic influ- 
ence of ether, chloroform, or chloral hydrate it is possible to 
arrest the processes of mitosis at different stages with the result 
that the protoplasm may become variously distributed in the 
daughter cells. (1) A daughter cell may be formed lacking a 
nucleus but containing a portion of the divided chromatophore 
in a peripheral layer of cytoplasm. (2) A single cell may con- 
tain the two daughter nuclei either separated from one another 
or more or less intimately associated and perhaps wholly fused 
depending upon how far the processes of mitosis have pro- 
gressed before the cells have been subjected to the shock of the 
