614 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
is in part coarsely fibrillar, in part finely fibrillar. The latter always 
forms the axis-cylinder process, but often expands from its base over 
the whole periphery of the ganglion-cell, which then shows a dark 
coarsely-fibrillar internal zone, and a clear finely-fibrillar internal zone. 
The ganglion-cells lie imbedded in the neuroglia, which consists of 
fibrils, like the coarse fibrils of the ganglion-cell’s spongioplasm, and 
containing many nuclei. At the periphery of the ganglion-cell the 
neuroglia fibrils are thicker, show more nuclei, and pass continuously 
into the coarsely-fibrillar spongioplasm. Therefore it Is concluded that 
the spongioplasm of the ganglion-cell is only a supporting framework, 
and that the really nervous substance is the enclosed hyaloplasm. 
Rohde has extended his observations to Nematodes, Molluscs, Crus- 
taceans, Insects, and Vertebrates, and has confirmed the above con- 
clusions. In Invertebrates, from Chfetopods upwards, the nerves consist 
of two kinds of elements. There is the PunJdsubstanz, which appears 
coarsely granular or fibrillar in section, and there are more or less broad 
axis-cylinder processes, which consist of a very finely fibrillar axis- 
cylinder and a sheath coarsely fibrillar like the Piinktsubstanz. In the 
lower Invertebrates the Punldsubstanz predominates, in the higher 
the axis-cylinder processes; i. e. as we ascend they become less like 
sympathetic and more like cerebro-spinal nerves. The general con- 
clusion, however, is that the spongioplasm is a supporting framework, 
and the hyaloplasm alone nervous. 
Study of ’Glandular Cells.* — M. J. Mouret has made a study of the 
activity of glandular cells, taking the pancreas as his organ for investi- 
gation. He finds that a pancreatic cell in a state of repose exhibits a 
zone full of large zymogenous fuchsinophilous granules and an external 
matrix zone. The nucleus is found at the boundary between these two 
zones. In addition to the granules the protoplasm is composed of two 
substances — one homogeneous and amorphous, and the other capable of 
staining by hsematin. During secretion there is formed in the proto- 
plasm a number of vacuoles, which contain a colourless fluid. The cell 
excretes its zymogenous granulations, which are dissolved in the liquid 
and form the pancreatic juice. The solution of the granulations may be 
made in the cell itself, but it more often takes place in the cavity of the 
secreting tube, or in the primary excretory cejls. At the same time as 
the cell excretes its zymogenous granulations and the contents of its 
vacuoles, the pre-zymogenous substance, or that which is stainable by 
haematin, increases in quantity. This last gradually breaks up into fine 
granulations, which extend through the whole protoplasm, where they 
gradually grow and ripen, to become in their turn true zymogenous 
granulations. 
A Tissue Transitional between Cartilage and Bone.f — M. J. Chatin 
finds that the sclerotic plates in the Gecko ( Platydactylus fascicularis 
Daud.) consist of a remarkable form of cartilage, with ramified anasto- 
mosing cells, similar to that found in Chimsera and in the cranial 
cartilage of Cephalopods. It is neither hyaline nor fibro-cartilage, but 
is like osseous tissue arrested midway in its development. 
* Journ. Anat. et Physiol., xxxi. (1895) pp. 221-36 (1 pi.). 
f Comptes Rendus, exxi. (1895) pp. 172-4. 
