in Blechnum and Osmnnda. 
49 
changes which ensue during their secretion, and we found that 
the drops appear to consist in the first instance of a clear 
gummy mucilage. This substance experiences further change, 
and in the fully developed structure we are able to distinguish, 
in each drop, a number of secondary spherical droplets which 
now give the reactions of pure gum. Thus the protoplasm 
gives rise to a gummy mucilage, and the latter undergoes 
further differentiation into a ground-substance, which still 
retains its mucilaginous character, and into a gummy sub- 
stance (the product probably of maximum chemical change) 
which is present as a number of isolated spherical droplets. 
In the mature gland the various drops are disseminated 
throughout the substance of the protoplasm, so that the 
protoplasm itself appears as a delicate reticulum or framework 
which contains the various drops in its meshes. It is a point 
of great interest to us that our results tally in a most remark- 
able manner with those obtained by Langley, in his research 
on the structure of animal secreting glands. We may even 
compare his description with our own, and if we provisionally 
eliminate from consideration the cell-wall, the cell-vacuole, 
and the plastids as being especially associated with plant 
cells, it will be seen that there is a great similarity between 
the two structures. The particular paper we quote from 
appeared in the ‘ Proceedings of the Cambridge Philosophical 
Society 1 .’ We necessarily somewhat condense Langley’s 
remarks. He writes, ‘ The secretory glands have the following 
common points of structure. The cell substance is composed 
of (a) a framework of living substance or protoplasm, con- 
nected at the periphery with a thin continuous layer of 
modified protoplasm 2 . Within the meshes of the framework 
are enclosed two chemical substances at least, viz. ( b ) a 
hyaline substance in contact with the framework, and of (c) 
spherical granules which are imbedded in the hyaline sub- 
stance.’ We do not wish to press the similarity too far, 
since we are aware that in establishing comparisons between 
1 Langley in Proe. Camb. Phil. Soc., Vol. v (1883), p. 25. 
2 Our ectoplasm. 
E 
