THE NEWTS STOMACH DURING DIGESTION 423 



18 Hours afterfood. 



The stomach is now empty. 



The lumen and cells hâve returned to their resting condition, being 

 full of zymogen granules situated in the meshes of a pale blue spongio- 

 plasm. 



The nuclei are somewhat angular and smaller than in the preceding 

 spécimens. They hâve returned to their normal resting condition with the 

 exception of a few that are still somewhat cloudy. The lanthanin granules 

 are of a pale slate blue colour and the chromatin deep blue. The nucleoli 

 are small and of the usual venons red colour and their extrusion appears to 

 hâve almost ceased. Near the pyloric end the cells hâve also almost corne 

 to rest. 



19 Hours and 20 hoiirs afterfood. 



Cell still resting and ail nuclei clear showing that they also hâve be- 

 come fuUy recuperated after sécrétion and are at rest. Mitotic figures are 

 fréquent. 



From thèse experiments it is évident that the gland cells of the stomach 

 are not capable of continued sécrétion for a prolonged period without rest ; 

 and that they exhibit marked periodicity. It would appear that they do 

 secrète actively for about 4 1/2 hours after which they require to rest for a 

 like period and that should there be still undigested matter in the organ 

 they may again enter into another period of active sécrétion lasting some 

 4 1/2 hours followed by another recuperative stage which takes a like interval 

 of time for its completion. 



This phenomenon of periodicity in the gastric gland cells has already 

 been ascertained by Ide and his pupils in the case of man in a séries of 

 very interesting experiments, the results of which hâve been published in 

 " La Cellule -. ■ 



Another point worth notice is the rapidity with which new zymogen 

 granules reappear in the cells after those previously stored up hâve been 

 exhausted followed by the slow récupération of the exhausted nucleus. This 

 point I think is well explained by the work of Macallum" and his pupils 

 on the existence of a prezymogen in gland cells, which is quickly transformed 

 into zymogen granules at the required time. It is the production of this an- 



