PROTOPLASM THROUGH THE WALLS OF VEGETABLE CELLS. 
853 
particular attention drawn to the fact; on the contrary, it has been generally accepted 
that on plasmolysis the protoplasm is quite free from the cell-wall. 
However, in repeating these experiments I find that in all the cases I have 
examined the contracted protoplasm is always connected to the cell-wall by means of 
very numerous protoplasmic threads. 
The above phenomena were also discovered subsequently and independently by 
Bower," whose excellent paper on the subject appeared shortly after my own. My 
experiments were first made upon pulvini, but were afterwards extended to tissues 
in general (figs. 34, 35, 36, 37). 
The most detailed observations were made upon transverse sections of the pulvini 
of Amicia zygomeris and Robinici pseudacacia, after treatment with 2‘5 per cent., 
5 per cent., and 10 per cent, solution of sodium chloride, but since the results 
obtained in other cases differ so little, one may describe the phenomena which 
accompany plasmolysis in general terms. 
If a dilute solution of salt be employed, e.g., 2’5 per cent., the protoplasm will 
gradually contract away from the cell-wall, and will at length frequently appear to 
lie quite freely in the cavity. In other cases the protoplasm will adhere to the cell- 
wall at certain points. But if the section be examined for some time, it will be seen 
that delicate strings of protoplasm will gradually come into view, and increase in 
number, until at length the contracted protoplasmic mass will present the appearance 
of a sphere suspended in the cell cavity by innumerable fine protoplasmic strings 
(Plate 70, fig. 37). 
If contraction be rapidly brought about by means of a stronger solution, e.g., 10 
per cent., it will be observed that the protoplasm experiences some difficulty in 
separating from the cell-wall, and may even become divided up during the process into 
two or more portions (Plate 70, fig. 35), each of which rapidly assumes a spheroidal 
shape; also several somewhat thick threads may be seen connecting the protoplasm 
to the cell-wall or the protoplasmic masses to one another (figs. 35 and 36). Subse¬ 
quently the finer threads come into view. I am inclined to believe that it is these 
thicker threads which have been hitherto seen, and that the finer threads have, up till 
now, escaped observation ; and although, as Bower! remai'ks, the difference between 
the thicker and the finer threads is only one of degree, yet the importance of the 
observation is in no way diminished thereby. 
The thicker threads frequently present nodal swellings of a perfectly spherical form. 
These spherical nodes may either abut on to the cell-wall or may occupy any other 
position upon the thread. When, by chance, rupture of the threads occurs, part 
contracts to the central protoplasmic mass, and part forms a small sphere on the side 
of the cell-wall. 
The first indication of the existence of the fine threads is afforded by an appearance 
* Quart. Jour. Micr. Sci. Jan. 1883. 
t Loc. cit. 
5 R 
MDCCCLXXXIII. 
