IV. On llio continuity of tho protuplasm through the walls of vegetable cells. 53 
In the summer of 1882 while working at the Wttrzburg laboratory 
umler Ihe direction of Professor Sachs, I succeeded in demonstraliug that in 
various pulvini, a direct communication betwecn the cells is established 
by means of delicate proloplasmic lilamenls which traverse the pit-closing- 
membranes'). In subsequent papers 1 2 3 ) I have detailed my further experimenls 
and results, which are inoreover confirmed by the researches of Küssow 11 ) 
m ho has proved that in the hast parenchyma cells and in the phloem-ray- 
cells of numerous planls e.g. Populus, Salix &c, the closing membranes of 
the pils are perforated by line protoplasmic threads. Thus at length evidence 
appearod that in cells such as those of pulvini which unlike sieve-tiibes 
cannot be regarded as modified for the purpose of serving as mere channels 
for eonduclion, and unlike inert endosperrn cells are in active life — in 
such cells there is also an actual communication betwecn one cell and 
another. 
In the present paper I propose to give an account of my work as far as 
il has as yet progressed in which I claim to have proved that in various 
pulvini, in the cells of the leaf of Dionaea, in the parenchyma-cells of the 
stamens of Herberts, in a great number of endosperrn cells, und in various 
ordinary vegetable lissue, there exisls a demonstrable Connection betwecn 
the protoplasmic contents of adjacent cells. 
/. Melhods. 
As it was important in a researeh of this kind that the material em- 
ployed should be preserved with the minimum amountof change, a number 
of experimenls were instituted in Order to determine which of the many 
preservative reagents generallv in use was tho most servicable. VVheu — as 
I shall point out later on — the plasmolytic condition is induced in a cell 
by treating it for some time with a 10 per cent solution of common salt, the 
protoplasm is caused to contract and separate away from the cell-wall, to 
which however it is still connected by delicate protoplasmic strings. Such 
plasmolysed lissue affords very favourable material for testing the relative 
fixing and preserving power of reagents. ln addition I also investigated the 
effects produced on sections of fully grown tissue possessing large vacuoles, 
and upon the filaments of Spirogyra and other filamentous Algae. Alcohol, 
I per cent Osmic aeid, 3 per cent Chromic acid, alcoholic and watery Solu¬ 
tions of alum, and corrosive Sublimate, saturated watery and alcoholic Pieric 
acid were used. The strengths of the Solutions were also varied, as occasion 
required since it seemed to me that owing to the diluting effect of the cell 
1) Gardinkr. Quart Journ. Micr. Soc. Oct. 1882. 
2) Gardiner. Roy. Soc. Proc. Nov. 11. 1882 d. Roy. Soc. Proc. April 16. 1883 & Roy. 
Soc. Proc. Dec. 20. 1883. 
3) Russow. loc. cit. 
