Seedlings of Zea Mais and Phoenix dactylifera . 285 
unfortunately, has not been performed) for determining which of the two 
hypotheses (if either) is correct. 
Concerning the nature of the various granules in the cells little can be 
said with any degree of certainty. They appear to arise as products of 
cellular activity, yet Muller (’ 96 ) believes that they are the elementary 
organs of the cell and are capable of growth and division. It is hoped that 
a wider application of the methods of physiological chemistry will supple- 
ment the results thus far obtained by the methods of histology. 
The extrusion of solid substance from the nucleus has been reported 
by many observers, but I have not been able to find any indications of it in 
my study. In every case it appeared as though the exchange of substances 
was accomplished when they were in a liquid state. It must be borne in 
mind that the soluble proteids would be precipitated by the reagents used 
in killing and dehydrating, and therefore granules in the prepared sections 
are not necessarily indicative of their presence in the living cell. 
Throughout the progress of the work I have been impressed by the 
similarities between enzymes and protoplasm in their manner of origin, 
action, and ultimate dissolution. Many of the similarities have been pointed 
out by Bokorny (’00). The two substances react similarly to most stimuli, 
except that enzymes show a greater resistance to destructive agents such as 
temperature, light, chemicals, &c. The decomposition of certain substances, 
e. g. sugar, by enzymes and protoplasm is very similar. 
The passage of two currents through the epidermal cells, one toward 
the endosperm and one toward the seedling, is undoubtedly brought about 
by osmosis modified by the selective action of the protoplasmic membrane. 
The existence of starch in the scutellum of Zea Mais shows that very little 
diastase passes toward the young plant. 
V. Summary. 
1. The results obtained in fixed and stained material are dependent to 
some extent upon the technique. 
2. In the resting condition the secreting-cells of both Zea and Phoenix 
are crowded with relatively small proteid granules. As secretion begins 
these granules gradually disappear. In Zea this disappearance coincides 
closely with the consumption of the endosperm ; in Phoenix , however, the 
granules disappear long before the endosperm is dissolved. 
3. The chromatin of the nuclei is small in amount at the beginning of 
secretion and increases as germination progresses. The nucleolus diminishes 
in size as germination progresses. These changes are more noticeable in 
the case of Zea than in Phoenix. 
4. There is no evidence that solid matter is extruded from the nucleus. 
5. At the close of secretory activity the protoplasm of the secreting- 
cells breaks down and the products of disintegration disappear from sight. 
