24 



Mr. J. N. Langley. 



[Apr. 27, 



granules and much glycogen, are kept at about 20° C. for a week to a 

 fortnight, the cells become granular throughout and the glycogen 

 largely disappears ; similarly frogs in spring or autumn, the liver- 

 cells of which have many granules and little glycogen, if kept at a 

 low temperature a week to a fortnight, present in the cells of the liver 

 an outer non-granular zone and an increase of glycogen ; in summer 

 frogs the effect is much less. Further, the changes during digestion 

 are slight in winter frogs that have been kept in the warm, greater in 

 spring and autumn frogs which have been kept in the cold. 



Although, generally speaking, a decrease of granules goes hand-in- 

 hand with -an increase of glycogen and an increase of granules with a 

 decrease of glycogen, yet a certain amount of variation in the one 

 may take place without any variation or any corresponding variation 

 in the other. Hence I regard the formation of granules and the 

 formation of glycogen as independent processes. A comparison of 

 the changes which take place in the granules of the liver-cells with 

 the changes which take place in the granules of the salivary, gastric, 

 and pancreatic glands leaves me with no doubt that the granules of the 

 liver-cells are destined to give rise to some constituent or constituents 

 of the bile, and it seems to me more than probable that by appro- 

 priate chemical treatment, we may obtain from them some one or 

 more of the constituents of the bile-salts. 



In the aecount I have just given I have omitted all mention of the 

 fat globules. These vary so much with different conditions of the 

 body, as yet unknown, that it is extremely difficult to determine what 

 changes in their number and position take place during digestion. It 

 is well known that there is in winter an increase in the amount of 

 fat in the liver. Generally speaking, in summer the fat globules are 

 small, few, and fairly equally scattered throughout the cell, with a 

 tendency to be more numerous around the lumen. In winter frogs 

 the greatest variation occurs, occasionally there are very few, usually 

 there are a considerable number, not unfrequently the cells are 

 crowded with them, this is generally the case with obviously un- 

 healthy frogs. Further, in the most common condition, that in which 

 the fat globules are fairly numerous without being crowded together 

 in the cells, they may occur almost entirely in the inner or almost 

 entirely in the outer part of the cell. In the former case they make 

 a conspicuous fat globule zone about the lumen, in the latter they 

 occur in conspicuous clumps close to the outer cell-border ; this is 

 generally the case when one has reason to suppose that fat is increasing 

 in the cells. If winter frogs are kept in the warm, the fat globules 

 diminish in number ; if summer frogs are kept in the cold for a week 

 to a fortnight there is a slight, but only a slight, increase in the quan- 

 tity of fat. The majority of frogs which are fed in the summer show 

 little or no change in the number or size of fat globules in the liver. 



