On the Secretory Cells. 



73 



rently embedded in a homogeneous mass, which other reagents show 

 to be composed of network and hyaline substance. 



The same cells, after treatment with alcohol, show an indistinct 

 network, containing an interfibrillar mass in which the granules and 

 the hyaline substance cannot be separately seen. 



The oesophageal glands of the frog and the pancreas of all ani- 

 mals, after treatment with alcohol, show the shrunken remains of the 

 granules, but leave the network and hyaline substance indistinguishable 

 or nearly so. 



Even chromic acid which in most gland-cells brings out the net- 

 work clearly, does not act in quite the same manner on all gland- 

 cells, for it differentiates the network and hyaline substance less 

 clearly in the oesophageal glands of the frog, than in the salivary 

 and gastric cells ; and differentiates them less clearly in the pancreas 

 than in the oesophageal glands of the frog. 



It will be noticed that the cells mentioned above form a series 

 in which the network and hyaline substance are less and less easily 

 distinguished from one another, that is, a series in which the net- 

 work and hyaline substance become more and more alike in chemical 

 characters. 



In the above general description I have not included the pyloric 

 gland-cells, the border cells (Belegzellen) of mammalian gastric glands, 

 or the semi-transparent chief-cells which are found in the latter part 

 of the greater curvature in some animals. In these the changes 

 described above as taking place in digestion have not yet been ob- 

 served. This, I think, is due to their containing very small granules, 

 which are not obvious during life, and which are not preserved by 

 any reagent; in consequence a change in their granularity is very 

 difficult to observe. 



With regard to their structure they certainly have a framework 

 enclosing hyaline substance, the only difficulty is to show that they 

 contain also granules embedded in the hyaline substance. 



These cells in life do not show distinct granules, but when they 

 are teased out in salt solution they become very finely granular. This 

 is not caused by the cell network, for the network has rather 

 large meshes. In those chief-cells which are apparently homogeneous 



