[ 663 ] 
XVI. On the Histology and Physiology of Pepsin-forming Glands. 
By J. K Langley, M.A., Fellow of Trinity College, Cambridge. 
Communicated by Dr. M. Foster, F.R.S. 
Received March 11,—Read March 24, 1881. 
[Plates 77, 78.] 
Contents. 
Rana temporaria. Page 
The structure of the oesophageal and gastric glands. 
The oesophageal glands. 664 
The oxyntic glands . 665 
The glands in the junction of tbe oesophagus and stomach. 667 
The pyloric glands ... 668 
The glands in the intermediate zone .. „... 669 
The changes which occur in the oesophageal glands during digestion. 669 
The changes which occur in the oesophageal glands when the animal is fed with sponge.. 671 
On some disputed points in the histology of the oesophageal glands... 672 
The changes which occur in the oxyntic glands . 674 
The changes which occur in the pyloric glands and in the necks of the oxyntic glands . . 677 
The pepsin-content of the oesophageal and gastric glands . 678 
BUFO VARIABIXiIS. 
Histology of the oesophageal and gastric glands ... 683 
Changes which occur in the oesophageal and gastric glands... 684 
Pepsin-content of the oesophageal and gastric glands. 685 
Triton tasniatus. 
Histology of the gastric glands ...... 686 
Changes which occur in the oxyntic glands.... 687 
Pepsin-content of the gastric glands .. . 689 
Triton cristatus .. 690 
Coluber natrix. 
Histology of gastric glands in hunger and digestion ... 691 
Pepsin-content of various regions of the stomach in hunger and digestion. 693 
General Conclusions and Remarks. 
Pepsin arises from the cell-granules ....... 694 
The cells store up zymogen and not pepsin .... 696 
The capability of distinguishing zymogen in living glands. 697 
The causes of the morphological changes in any one gland-cell.. 698 
Comparison of the effect of digestible and indigestible food.... 702 
The causes of the different morphological changes in different gland-cells .. 703 
In the cells there is during secretion an increase of substance capable of reducing osmic acid 706 
