1881.] 



On the Coefficients of Expansion, Sfc. 



23 



non-granular zone, the oxyntic glands* of Triton tceniatus, form nor- 

 mally a less developed, thongh distinct, outer zone, this being less in 

 the posterior than in the anterior oxyntic glands. In the glands of 

 Triton cristatus, the outer zone is reduced to a minimum, or is repre- 

 sented only by a greater thinning out of granules in the peripheral 

 part of the cells ; the scanty oesophageal glands of the toad show 

 a bare trace of a similar difference in the two parts of the cell. In the 

 greater number of the oxyntic glands of the snake, and in the anterior 

 oxyntic glands of the stomach of the toad, neither an outer nor an 

 inner zone is formed, but in passing backwards to the posterior oxyntic 

 glands in both of these animals, an inner non-granular zone gradually 

 becomes obvious. The inner zone reaches its greatest development, so 

 far as I have observed, in the posterior oxyntic glands of the frog. 



In this brief account the general conclusions which can, I think, 

 be drawn from the study of the pepsin-forming glands are only given, 

 I have made no reference to the important papers of Heidenhain, 

 Griitzner, Swiecicki, Nussbaum, Partsch, and others on the same 

 subject. I have discussed their work in the fuller paper, which con- 

 tains the details on which the conclusions here given are based. 



March 31, 1881. 

 THE PRESIDENT in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



1. " On the Coefficients of Expansion of the Di-iodide of Lead, 

 Pbl 2 , and of an Alloy of Iodide of Lead with Iodide of 

 Silver, PbI 2 .AgI." By G. F. Rodwell, F.R.A.S., F.C.S., 

 Science Master in Marlborough College. Communicated 

 by Professor A. W. Williamson, For. Sec. R.S. Received 

 March 10, 1881. 



(Abstract.) 



The author having referred to his previous papers on the co- 

 efficients of the iodides of silver and mercury, and of certain chloro- 



* I propose to use the term " oxyntic" (o%vvuv, to make sour, to acidulate) for 

 those glands which are called by different observers by the inappropriate names 

 "fundus," " peptic," or " rennet" glands. 



