in Blechnum and Osmunda . 
33 
of young paleae and leaves, the attention of the observer is 
soon drawn towards the large swollen mucilage-cells. They 
may be seen in various stages of development, and perhaps 
the more usual and typical forms are those represented by 
Figs. 5, 6 and 7. 
The glands of the paleae are more conspicuous than those of 
the leaf on account of their greater size and the more highly 
refractive character of the mucilage secreted by them. The 
latter substance occurs in the younger glands as a number of 
brightly shining isolated drops (Fig. 5), which soon appear to 
lose their distinct outline and to become clubbed together 
into a single irregular and lobular mass (Fig. 6). Later on, 
the entire cell appears to be filled with the mucilaginous 
secretion, which is highly refractive and contains a number of 
darker granules disseminated throughout its substance (Fig. 9). 
In other gland-cells the mucilage appears to be differentiated 
into an inner and granular central mass surrounded by a broad 
and hyaline outer layer (Figs. 7 and 8), and here almost 
any one would suppose that at any rate a portion of the 
mucilage arises from the degeneration of the inner layers 
of the cell-wall. Lastly, careful observation will usually 
demonstrate that in the isolated drops which are shown so 
well in the younger gland-cells, numerous minute droplets are 
present which may moreover be recognised in the older 
glands also (Figs. 10, 11 , 12 and 8). The protoplasm is in all 
cases clear and difficult to define. 
We may at once remark that in reality all the mucilage is 
secreted by the protoplasm, and that in the very oldest cells 
remains of the ectoplasm and of the nucleus can be shown to 
be present outside the mucilage-mass. The very transparent 
character of the protoplasm causes the satisfactory demonstra- 
tion of this fact to be often a matter of some difficulty, and we 
found this to be especially the case in our investigations con- 
cerning the origin and development of the mucilaginous drops. 
Again and again, from every standpoint we have returned to 
this question, and after numberless observations we feel that 
we have established beyond all doubt that the whole of* the 
D 
