72 



J. N. Langley, 



In the gastric glands of the snake, the decrease in the granules, 

 and the increase of the hyaline substance, is equal or nearly equal 

 in all parts of the cell. In the gastric glands of the frog and toad, 

 whilst the same changes are most marked in all parts of the cell, 

 they go on most rapidly in a narrow strip next the lumen. In the 

 liver cells of mammals, the changes are most active in the central 

 part of the cells around the nucleus. 



It is to be remembered that there is reason to believe, that the 

 three parts of the cell are continually being formed and changed 

 into other substances ; the extent of the change which can be obser- 

 ved in a cell during secretion depends upon the relative rates at 

 which these processes go on. I have previously pointed out l ) that 

 different gland -cells vary considerably with regard to the different 

 relative rates at which the formation and breaking down of their con- 

 stituents take place. 



The differences shown by the different cells after the same treat- 

 ment, depends, partly upon the different chemical characters of the 

 framework, hyaline substance, and granules in the different cells, and 

 partly upon the different arrangement of these constituents. With 

 regard to the former of these causes of difference a few instances 

 may be given. 



In the rabbit's sub -maxillary gland, after treatment with osmic 

 acid, the granules are indistinguishably mixed with the hyaline sub- 

 stance; and the resulting mass differs so little in refractive and 

 staining power from the network, that the nodal points only of the 

 network are at all distinctly seen. 



In the chief- cells of the cat's gastric glands, after treatment 

 with osmic acid, the granules and hyaline substance are also in- 

 distinguishable; but the network is much more distinct than the 

 network in the rabbit's sub-maxillary gland. The network is however 

 much less distinct than in a gland that has been treated with chro- 

 mic acid. 



In the chief-cells of the bat's gastric glands, after treatment with 

 osmic acid, the granules are perfectly distinct, but they are appa- 



*) Transact. Royal. Soc. Part IIL 1881. 



