368 R. R. bp:nsley. 



of large meshes, and in thick sections present a vacuolated 

 appearance. The protoplasmic strands which compose this 

 network are very coarse, and stain readily in hsematoxylin, a 

 feature which is particularly noticeable at the thickened nodal 

 points. 



In sections stained in gentian violet or safranin the ap- 

 pearance depends on the degree of success attained in fixing 

 the zymogen granules. If they are well preserved they stain 

 intensely in these dyes, and the cell is then seen to be filled 

 with large deeply stained granules, between which may be 

 seen running the trabeculae of the protoplasmic framework. 

 If the fixation is less successful the granules are found to 

 have swollen up, so that the whole cell stains diffusely — afford- 

 ing, however, unmistakable evidence of the presence of 

 zymogen. 



The relation between the granules and the protoplasm may 

 be clearly seen in sections stained in the Biondi three-colour 

 mixture, in which the granules stain a pale blue and the proto- 

 plasm red. In sections thus stained each granule is found to 

 correspond to a mesh of the protoplasmic network. This is, 

 then, not a true network, but simply the optical expression of 

 the fact that the zymogen granules occupy small cavities in 

 the cell, which are separated from one another by thin films of 

 the protoplasm of the cell. In hardened cells there is usually 

 a clear space surrounding each zymogen granule, but it is to 

 be inferred that in the living resting cell the granule com- 

 pletely fills the cavity in the protoplasm which it occupies. 



In the base of the cell, even after a prolonged fast, there 

 may usually be seen a small quantity of protoplasm which, on 

 account of the peculiar properties it presents, seems to merit 

 a more extended description than is usually accorded it. 



Langley i observed that the protoplasmic zone of the active 

 cell contains a substance which stains more readily with osmic 

 acid than ordinary protoplasm, and which he inferred to be 

 one of the earlier steps or mesostates in the formation of the 



' 'Phil. Trans. Roy. Soc.,' vol. clxxii. 



