CKLLS IN THE PULVINUS OF MIMOSA PUDICA. 365 



Note on Open Communication between the Cells in the 

 PuLviNus of Mimosa pudica. By Walter Gardiner, 

 B.A., late Scholar of Clare College, Cambridge. 



An anatomical investigation of the organs of motion in 

 certain plants which I have undertaken at the suggestion 

 of Professor Sachs has already led to some results which 

 appear of sufficient interest for publication. A point of 

 primary importance was to endeavour to ascertain whether 

 any means of communication exists between the protoplasm 

 of neighbouring cells. My attention has as yet been chiefly 

 occupied with a study of the pulvini of Mimosa, Robinia, 

 Amicia, and Phaseolus. 



The parenchyma of the organs of motion in these plants 

 in common, so far as I am aware, with that of all pulvini, is 

 very strongly pitted, and as a result of my investigations it 

 appears certain in the case of Mimosa, and most probably in 

 the case of the other three, that by means of these pits 

 there is a direct communication from cell to cell, or, in other 

 words, that the pits are open. My method of preparation 

 of the cells of the pulvinus, upon which these results in a 

 great measure depend, is a modification of that first used by 

 Sachs for the demonstration of sieve-pores, the only difierence 

 being that aniline colours instead of iodine are used as the 

 staining reagent. The best results were obtained with thin 

 sections of the fresh material. On treating such a section 

 first with strong sulphuric acid and then with the aniline 

 colour, or with a mixture of strong sulphuric acid and aniline 

 colour, the middle lamellae of the cells remain as a fine net- 

 work, the cellular cell-walls are dissolved or rendered 

 invisible, and the protoplasm presents the appearance of a 

 deeply stained, irregularly shaped mass lying in the swollen 

 colourless substance of the cell-wall. 



From these irregularly-shaped masses radiate numerous 

 fine processes from the central mass to the middle lamella. 

 In any two neighbouring cells the processes from the one 

 central mass meet exactly those proceeding from the other, 



