SECRETION OF SALIVA AND GASTRIC JUICE. 



273 



FIG. 87. 



420 



which does not stain readily. In the cell which after great activity has 

 discharged itself, the cell is smaller, but what remains is largely living 

 cell-substance, some of it new, and all stain- 

 ing readily. It would appear also, that dur- 

 ing the activity of the cell some substances, 

 capable of being precipitated by alcohol, make 

 their appearance, and the presence of this ma- 

 terial adds to the turbid and granular aspect 

 of the cell ; possibly, also, this material con- 

 tributes to the staining. A similar material 

 seems to make its appearance in the cells of 

 albuminous glands. 



In the ovoid or border cells no very charac- 

 teristic changes make their appearance. During 

 digestion they become larger, more swollen, as 

 it were, and in consequence bulge out the base- 

 ment membrane, but no characteristic disap- 

 pearance of granules can be observed. In the 

 living state, the cell-substance of these ovoid 

 cells appears finely granular, but in hardened 

 and prepared sections has a coarsely granular, 

 " reticulate " look, which is perhaps less marked 

 in the swollen active cells than in the resting 

 cells. 



207. All these various secreting cells, 

 then pancreatic cell, mucous cell, albuminous 

 cell, and central gastric cell exhibit the same 

 series of events, modified to a certain extent in 

 the several cases. In each case the " proto- 

 plasmic" cell-substance manufactures and 

 lodges in itself material destined to form part 

 of the juice secreted. In the fresh cell this 

 material may generally be recognized under 

 the microscope by its optical characters as 

 granules; these, however, are apt to become 

 altered by reagents. But we must guard our- 

 selves against the assumption that the mate- 

 rial which can thus be recognized is the only 

 material thus stored up; we may in future, 

 by chemical or other means, be able to differ- 

 entiate other parts of the cell-body as being also material similarly 

 stored up. 



During activity, while the gland is secreting, this material, either 

 unchanged or after undergoing change, is wholly or partially discharged 

 from the cell. The cell, in consequence of having thus got rid of more 

 or less of its load, consists to a larger extent of actual living cell-sub- 

 stance, this being in many cases increased by rapid new-growth, though 

 the bulk of the discharged cell may be less than that of the loaded cell. 



This activity of growth continues after the act of secretion, but the dis- 

 charged cell soon begins again the task of loading itself with new secretion 

 material for the next act of secretion. 



Thus in most cases there is, corresponding to the intermittence of secre- 

 tion, an alteration of discharge and loading ; but it must be borne in mind 

 that such an alteration is not absolutely necessary, even in the case of inter- 

 mittent secretion. We can easily imagine that the discharge, say of 

 18 



Gastric Gland of Mammal (Bat) 

 during Activity. (Langley.) c, the 

 mouth of the gland with its cylin- 

 drical cells, n, the neck, contain- 

 ing conspicuous ovoid cells, with 

 their coarse protoplasmic net- 

 work. /, the body of the gland. 

 The granules are seen in the cen- 

 tral cells to be limited to the inner 

 portions of each cell, the round 

 nucleus of which is conspicuous. 



