No. 466.] STUDIES ON PLANT CELL. — VIII. ^33 



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 Zygneroa and Spirogyra and 

 noting the ability of their chromatophores to form starch in 

 considerable quantities but the inability of the prdtoplast 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- 



