464 Ferguson . — The Development of the Egg and 
the nucleolus consists of substances which stand in some 
relation to the nutritive processes of the nucleus, and so, at 
the time of its formation, may be a functionless, inert mass of 
matter, yet it may at later periods in the history of the resting 
nucleus, acquire some active function, and thus gradually come 
to acquire the value of a nuclear organ.’ 
The nucleolus of the egg-nucleus, as also the nucleoli of the 
sheath-cells in Pinus Strobus , appear to represent active 
portions of the cell rather than inert masses of matter. 
Certain aspects presented by these nucleoli are surely sugges- 
tive of plastids. The uncoloured framework of the egg- 
nucleus reminds one very strongly of a chlorophyll-body 
from which the pigment has been extracted. Yet we would 
not, in the present state of our knowledge, denominate them 
plastids. I believe, however, although the phenomena are 
not of such a nature as to admit of definite demonstration, 
that the nucleolus of the egg-nucleus, as also the nucleoli of 
the sheath-cells, is actively engaged in the formation of a 
substance which in the egg-nucleus assumes the shape of 
secondary nucleoli. These nucleoli become diffused through- 
out the nucleus, from which they pass, probably in solution, 
into the egg-cytoplasm. Here they are again differentiated, 
and by a gradual development, give rise to the { proteid 
vacuoles’ or nutritive spheres of the oosphere. It may be 
that the greater size of the egg-nucleus, in comparison with 
that of the sperm-nucleus, is correlated with the physiological 
role, as above suggested, which it plays in the cell. 
The Fate within the Egg of the Smaller Sperm- 
Nucleus, the Vegetative Nucleus, and the 
Stalk-Cell. 
When these nuclei first enter the oosphere there is no 
question as to their identity, to one who has become familiar 
with them before their exit from the pollen-tube (Figs. 40- 
42). Remnants of these cells have been found in the upper 
part of the egg as late as the formation of the eight-celled 
stage of the proembryo. The stalk-cell remains for some 
