414 Wm. S. Marshall and C. T. Vorhies, 



the new secretion is being added to tliat which has already been 

 formed and we could easily compare the conditions in glands which 

 had been resting for some time with those which had been active for 

 short or long periods. In nearly all of our preparations the secretion 

 had contracted and pulled away from the surface of the gland; such 

 places were selected, as the conditions here showed more distinctly 

 than where the two parts were in juxtaposition. Where the secretion 

 was at all removed from the gland the inner membrane of the cells, 

 as already mentioned, was pulled away and it was either attached to 

 the secretion or was in the space between it and the gland. Where 

 it was pulled away from the gland it generally carried with it a thin 

 layer of cytoplasm, which, tearing from the cell, left irregular and 

 somewhat jagged edges. If still quite near the cell slight strands of 

 cytoplasm connect the two (Fig. 25); if the separation is complete, 

 broken filaments of cytoplasm may be seen attached to the torn margin 

 of the cell and to the inner membrane (Fig. 24). In most specimens 

 there is present, just with the inner membrane, a small thin layer 

 having a structure resembling cytoplasm (Figs. 24, 25 and 27). Between 

 this latter layer, or, in its absence, the inner membrane, and the sur- 

 face of the darkly staining secretion is another layer nearly homogenous 

 in structure, and of a light brown color (Figs. 25 and 28). This is of 

 varying thickness, usually quite thin; where, however, any depressions 

 occur in the secretion, they are filled in by this layer. Next to this 

 lies the secretion, which in most sections- sends numerous processes 

 through the layer which we have just described (Fig. 24). The 

 margin of the light brown layer lying adjacent to the secretion 

 follows its irregularities, while the surface facing the gland is rough- 

 ened by many rather sharp processes projecting from it (Fig. 25). 



An examination of sections which have been active for two and 

 a half or for five hours show that but slight changes have taken place 

 (Fig. 25). The difference in the thickness of the light brown layer in 

 this and the preceding figure (24) does not signify any change, as in each 

 case the layer varies in different parts of the sections. It is noticeable 

 that in the layers on either side of the inner membrane there are a 

 number of minute granules which have been very darkly colored. 



