48 Mr Hardy and Mr McDougall, On the Structure [Jan. 30, 



which are preserved by osmic vapour and to a less extent by 

 corrosive sublimate. Since these granules accumulate in great 

 numbers in starving animals, and since it can be shown that they 

 make their way into the lumen of the gut there to swell up and 

 dissolve, we are justified in regarding them as secretory granules, 

 and the cells which bear them as gland cells, engaged in the 

 elaboration of a digestive ferment or ferments. 



In a series of sections of a gut preserved by most reagents 

 (osmic acid and corrosive sublimate excepted) there are usually 

 seen, apparently between the cells, clear spaces reaching from 

 basement membrane to striated border but usually not into the 

 border ; they vary in shape, in a gut taken from an animal during 

 digestion, from a narrow slit, straight or curved, according to 

 the shape of the cell, to broadly oval spaces, which seem to 

 compress the adjacent cells to a dice-box shape. 



Occasionally the striated border is discontinuous opposite these 

 spaces ; being perforated by a small canal which in oblique 

 sections often resembles a small vacuole. 



In cells preserved with osmic acid vapour, no such gaps be- 

 tween the cells occur, or if so, very rarely ; but there are seen 

 within the cells granules which are not seen in the specimens 

 where the gaps occur. 



These granules appear to stain rather differently with osmic 

 vapour in different cases. Sometimes only lightly, at other times 

 more darkly. 



In cells preserved with a saturated solution of corrosive sub- 

 limate the granules are generally only partly preserved. In some 

 cases each granule seems to be swollen up and to have become 

 clear and non-staining, but not to have fused with the neigh- 

 bouring granules, or only to a slight extent; the cell substance 

 then appears as a stained protoplasmic network of very fine 

 meshes, enclosing the clear swollen granules. 



The change in places goes further; the granules and the 

 network are no longer seen but in their place appear clear un- 

 stained patches chiefly at the bases of the cells. 



Absolute alcohol sometimes preserves the granules in part. 

 They then stain deeply with hsematoxylin. It may then often 

 be seen that in a cell some of the granules are swollen up and 

 coalesced into a clear non-staining mass, while the rest remain and 

 are very clearly seen. 



Wherever granules are well preserved they may be seen to 

 be arranged in vertical rows stretching from the basement mem- 

 brane to the cell border. 



In the middle region of a fasting gut preserved by osmic 

 vapour the cells are often very much distended laterally with 

 granules. The rods of the hyaline border then stand much further 



