30 Mr Langley, On the Secretory Cells. [Nov. 12, 



to be the expression of a growth and rearrangement of the cell 

 network. 



The non-staining substance is considered by Heidenhain, to be 

 substance stored up for secretory purposes, and comparable to the 

 zymogen granules of the pancreas ; with which I agree in part 

 only; I consider the non-staining substance to consist of hyaline 

 and of granular interfibrillar substance, the latter only correspond- 

 ing to the zymogen granules of the pancreas. In all these cases, 

 as in the pancreas, the granules disappear from the outer parts 

 of the cells during secretion, but in alcohol specimens this cannot 

 be observed. The active pancreatic cells differ in appearance 

 in stained alcohol specimens from the serous and other cells men- 

 tioned above, chiefly because, in the pancreatic cells, the hyaline 

 interfibrillar substance as well as the network takes up the colour- 

 ing matter. 



Another change has been described by Griitzner 1 and by myself 1 

 as occurring in various cells during secretion. The cells, after they 

 have been actively secreting, take a darker and browner tint on 

 treatment with osmic acid, than they take on similar treatment 

 after a period of rest. Formerly I referred this to the whole of 

 the non-granular part of the cell, in which I did not then dis- 

 tinguish a network and hyaline substance. The change of staining 

 power shown by the cells during secretion is however, I think, due 

 to a change in the hyaline substance, and not to a change in the 

 network. It is chiefly caused by the increased amount of hyaline 

 substance. I say chiefly, since it may be partly due to the fluid, 

 which permeates the cell, containing during secretion a greater pro- 

 portion of substance capable of reducing osmic acid than it contains 

 during rest. 



The question now naturally occurs, What is the nature of the 

 hyaline interfibrillar substance ? We have seen that as the 

 granules diminish, the hyaline substance increases, and that as the 

 granules increase, the hyaline substance diminishes ; so that an 

 obvious hypothesis is that the protoplasmic network forms the 

 hyaline substance and then out of this manufactures the granules, 

 which are, as we know, converted during secretion into some one 

 or more of the organic bodies of the fluid secreted. It is some- 

 what in favour of this hypothesis, that in peptic glands there are 

 apparently certain intermediate stages in the formation of pepsi- 

 nogen ; it may further be noted that in the liver-cells, the hyaline 

 substance is often indistinguishably mixed with a substance allied 

 to glycogen. 



On the above hypothesis it would I think be most natural to 



1 Arch.f. d. ges. Physiol, xx. § 399, 1879; Proc. Roy. Soc. xxix. p. 377, 1879; 

 Journ. of Physiol, n. p. 261, 1879; Trans. Roy. Soc. Pt. in. 1881, p. 663. 



