Seedlings of Zea Mais and Phoenix dactylifera . 279 
the form of fine granules. The nucleoli were spherical, well-defined bodies 
which stained dark purple. 
After the growth had been checked by low temperature for twenty-four 
hours there was a marked change in the appearance of the cells. The 
cytoplasm contained large lumps which stain dark purple. The staining 
property of these aggregations was more intense than that occurring in 
ordinary secretion. The nuclei had lost most of their chromatic substance 
and appeared quite clear. They contained at least one large nucleolus which 
had lost neither in size nor staining qualities. 
When normal conditions were restored, the cells appeared to regain 
activity. The fixed and stained material showed two things very clearly : 
(1) the aggregations had almost entirely disappeared from the cytoplasm, 
leaving it homogeneous purple ; and (2) the nuclei contained numerous large 
granules of chromatin, but the nucleoli had disappeared. It hardly seems 
possible that any of the nucleo-proteids are absorbed by the nucleus when 
activity is resumed. 
The fact that the nucleus contains granules only during resting periods, 
or periods of arrested growth, and is large, hyaline, and intimately connected 
with the cytoplasm during the time of most active secretion, indicates to my 
mind that the nucleus is not a storehouse of diastase in any form, but is the 
source of energy by which the diastase is produced. The view here taken 
is that the diastase is manufactured from other proteids and turned into 
secretion by the activity of the epidermal cells, in which processes the nuclei 
probably perform the largest part of the work. 
My own work fails to confirm many of the observations made by Torrey 
(’02). I did not find, at the beginning of secretion, the nuclei filled with 
dark staining granules. Nor did I find the granules being extruded in a 
solid state into the cytoplasm through breaks in the nuclear membrane. 
There were, it is true, in the resting stage, fine granules in the nucleus ; but 
they disappeared during the first two days and did not reappear. By far 
the greater amount of proteid granules was found in the cytoplasm of the 
epidermal and subepidermal cells before secretion began. Moreover, the 
granules in the cytoplasm differed both in size and staining qualities from 
those in the nuclei, and gradually disappeared as secretory activity pro- 
gressed. 
I likewise failed to find that the process of secretion in Zea is an inter- 
mittent one, in which periods of activity alternate with periods of rest. If 
the seedlings are grown at a constant temperature, the process of secretion 
is continuous while enzymes are being produced. In repeating Torrey’s 
methods I found that the use of Iron Haematoxylin as a stain was the 
cause of many differences in our observations, because it is not reliable 
in differentiating the various cell-constituents. As his own paper states, 
it stains everything alike in a very deceptive manner, and is the cause of 
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