269 
Seedlings of Zea Mais and Phoenix dactylifera . 
process lasts for a long time, the chromatin content increases farther and 
chromatin granules lie within the interior of the nucleus. Simultaneous 
with these changes the nuclear membrane becomes indistinct, and at times 
almost invisible. Miss Huie reported the same appearance and expressed 
the belief that the nuclear membrane was absorbed. Rosenberg believes 
that the membrane undergoes a change in composition and staining 
qualities which perhaps facilitates the communication between nucleus and 
cytoplasm. The nucleolus constantly grows smaller until at the close of 
secretion it is very small. Yet he thinks there is no close connexion 
between nucleolus and chromatin, for there are nuclei with abundant 
chromatin which nevertheless contain large nucleoli. Chromatin is ap- 
parently an active component of the nucleus, yet it remains an open 
question whether the increase of chromatin is the result of the formation of 
an enzyme, or of the abundant absorption of nutrition. He thought that 
the latter theory was improbable. 
In his work on the secreting-cells of the pancreas, Mathews (’99) found 
that during secretion the nucleus moves nearer the centre of the cell and 
that the fibrillar zone increases in size, while the granular and reticulate 
cytoplasm disappears. The granules called zymogen-granules arise as 
products of the decomposition of the threads which in turn are formed by 
the chromatin. Neither the nucleoli nor chromatin showed any periodic 
alteration in amount or staining reactions. The synthetic processes in the 
nucleus were thought to resemble in many ways catalytic or fermentative 
actions. 
Another interesting and careful study is that of Gamier (’00) on various 
animal glands, but his results are not different from those already given. 
While my work was still in progress, Torrey (’02) published an account 
of the cytological changes occurring in the cells of the scutellum of Zea 
Mais during the secretion of enzyme. His observations and conclusions 
differ from mine in many important respects, as I shall show later. 
He locates the origin of the diastase granules in the nucleus, where 
they exist as fine, deeply-staining granules. From the nucleus, fine rows 
of granules extend through the nuclear membrane and out into the cyto- 
plasm. After germination has progressed for about eighteen hours the 
cells are much larger than in the resting stage, the nuclei are for the most 
part devoid of granules, which are now to be found in the cytoplasm. 
After twenty-four hours certain cells are to be found in which the granules 
are massed together in the ends nearest the endosperm, but otherwise the 
cytoplasm and nuclei are entirely destitute of them. At the beginning of 
the second day of germination the secreting-cells are in a resting condition ; 
there is no increase in size and the nuclei are clear. 
The second period of secretion begins at the end of the. second day. 
It is indicated by the presence of darkly staining granules in the nucleus 
