180 



Mr. W. Gardiner. 



[Dec. 20, 



III. " On the Changes in the Gland-Ceils of Dioncea muscipula 

 during Secretion." By Walter Gardiner, B.A., Scholar 

 of Clare College, Cambridge. Communicated by W. T. 

 Thiselton-Dyer, C.M.G., F.R.S. Received December 18, 

 1883. 



The following observations were made upon leaves of "Dioncea mus- 

 cipula which had been fed with the bodies of wood-lice, from which 

 the chitinous coat had been previously removed. The leaves were 

 then placed in absolute alcohol. 



It is well known that shortly after the application of animal matter 

 the leaves close, and may remain shut for a period varying usually 

 from ten to twelve days, when they open spontaneously. When, 

 however, the leaf is not vigorous or when the amount of animal 

 matter is somewhat large, the leaf may not open at all, but remain 

 closed until its death. 



There appear to be four periods which attend the phenomenon of 

 digestion in such a leaf, viz., the resting, the secretory, and the absorp- 

 tive periods, and the period of recovery. These periods are fairly 

 well defined in Dioncea on account of the slowness with which they 

 proceed. 



In the resting state the gland cells (fig. 1) exhibit the following 

 structure: — In each cell, the protoplasm closely surrounds the cell- 

 wall, leaving one large central vacuole, which is filled with the usual 

 pink cell- sap. The protoplasm is extremely granular, especially 

 around the nucleus, which is, in consequence, almost entirely obscured 

 from view. The nucleus is situated at the base of the cell, and is 

 shown by reagents to be large and well-defined. 



Fig. 1. 



At the end of the secreting period, which appears to be about 

 twenty-four hours after stimulation, the following chaDges have 

 occurred (fig. 2). Movements of the protoplasm have taken place, in 

 consequence of which the nucleus now occupies the centre of the cell ; 

 numerous strands of protoplasm radiate from the nucleus to the 

 parietal protoplasm of the cell, in consequence of which several 



