No. 466] STUDIES ON PLANT CELL. — VII. 733 
cussed the relations of the nucleus to the surrounding proto- 
plasm with respect to both dynamics and morphology. Klebs 
(88) indeed anticipated some of the work of Gerassimow, study- 
ing the non-nucleated cells of Zygnema and Spirogyra and 
noting the ability of their chromatophores to form starch in 
considerable quantities but the inability of the protoplast to add 
to the cell wall. Klebs was able to keep these non-nucleated 
cells alive in a sugar solution for from four to six weeks. But 
for the most part the discussions of the balance of nuclear and 
cytoplasmic activities in the plant cell have been very general in 
character. 
Some principles have been, however, widely held for several 
years and may be summarized. The necessity of the nucleus to 
the life of the cytoplasm has been clearly understood but the 
studies of Klebs and Gerassimow indicate that the nucleus is not 
directly concerned with the process of photosynthesis which 
apparently may go on in non-nucleated cells as long as the cyto- 
plasm retains a certain degree of vitality. A non-nucleated cell 
may enlarge slightly but it is not probable that the amount of 
protoplasm is increased. An especially interesting feature of 
non-nucleated cells is the inability of the outer plasma membrane 
to form cellulose walls or outer membranes. But the very inter- 
esting studies of Townsend (97) have shown that this power 
may be retained provided the non-nucleated mass of. protoplasm 
is connected by delicate cytoplasmic fibrils with a nucleated 
mass. It thus seems clear that the membrane-forming possi- 
bilities of the outer plasma membrane are absolutely dependent 
upon dynamic relations with the nucleus. While the chromato- 
phore may carry on the processes of photosynthesis independ- 
ently of the nucleus, nevertheless the general health of the cell 
requires the activities of the latter so that the nucleus becomes 
necessary to any extended photosynthetic work. 
It has frequently been stated that the size of the nucleus is 
directly proportionate to the amount of cytoplasm in the cell. 
There are many favorable illustrations of this statement, as the 
extraordinarily large eggs of the gymnosperms, especially the 
cycads, whose nuclei are by far the largest in the plant kingdom. 
And in general an increase in the amount of cytoplasm is accom- 
