1879.] 



On Pepsin-forming (jr lands during Secretion. 



383 



II. ,; On the Changes in Pepsin-forming Glands during Secre- 

 tion.'" By J. N. Laxglet. M.A.. Fellow of Trinity College, 

 Cambridge, and H. Sewall, B.Sc. Fellow of the Johns 

 Hopkins University. Baltimore. U.S.A. Communicated by 

 Professor Mighael Foster. M.D., F.R.S. Received Oc- 

 tober 13. l£7 L J. 



The (Esophageal Glands of the Frog. (Rana tenrporaria.) 



In a frog three to four days after food the acini of the oesophageal 

 glands in the living state are granular throughout, and so thickly 

 granular that the outlines of the alveoli are but faintly indicated, the 

 outlines of the cells not at all seen, nor are there any indications of 

 nuclei. 



Shortly ai'ter food is given, the granules thin away at the peri- 

 pheries of the alveoli and so render the alveolar outlines more 

 obvious. This thinning proceeds so rapidly that in a fevr hours there 

 is a well-marked clear zone in the outer part of each alveolus, the 

 part nearest the basement membrane. 



Later the clear zone becomes larger, the granular zone becoming- 

 smaller, but as the clear zone enlarges it ceases to iorm in section a 

 ring, it dips down into the granular zone at intervals, or in other 

 words, the ceils in using up their stored granules do not all use them 

 up at the same rate, some are more energetic than others, so that the 

 granular zone takes in section a somewhat star shape. In addition to 

 this, the star-form of the granular zone is aided by the granules 

 along the margins being less readily used up than those in the 

 interior of the cells. 



ZSTuclei are as little seen in the digesting as in the resting gland. 

 The glands having then as digestion goes on got rid of a large number 

 of their granules, proceed to form others as digestion ceases. The 

 clear spaces between the points of the star are filled up. and the clear 

 zone forms granules from within outwards, until the granules once 

 more extend to the basement membrane, 



An indication of the changes taking place in the alveoli of the 

 glands can be seen in the oesophagus itself with the unaided eye : in 

 a hungry frog the oesophagus is an opaque white, in a digesting frog 

 it is greyer and more transparent. 



Frogs in an ill state of health do not show the full granular con- 

 dition characteristic of the hungry frog, the granules are much less 

 numerous, and often, indeed, do not extend to the basement mem- 

 brane : with these, however, as with healthy frogs, the granules 

 diminish during digestion. 



The granules we have hitherto spoken of may be called " central" 



