PROTOPLASM THROUGH THE WALLS OF VEGETABLE CELLS. 
855 
If, however, Spirogyra cells be plasmolysed, it will be seen that the whole structure 
has been much affected, for the chlorophyll bands will no more resume either their 
accustomed appearance or arrangement, and a general swelling of the cell takes place. 
The strings of protoplasm which normally traverse the cell vacuole in ordinary 
living cells frequently exhibit the same appearances as those which are presented by 
plasmolysed threads, and nodal swellings may also occur. I have observed this 
particularly well in the hypodermal cells of potato tubers.* 
I have also frequently noticed that as a result of plasmolysis many chlorophyll 
grains will tend to aggregate around the nucleus as if some connexion with the latter 
existed, such as Pringsheim observed in Spirogyra. t 
The point of special interest to me was to ascertain whether these threads bore any 
relation to the pits. As I stated in my paper before the Royal Society, I have 
observed several well defined instances in which threads do go to pits, and in Plate 70, 
fig. 34, which is a made-up figure embodying in one representation the results of 
numerous individual cases, I have attempted to illustrate such appearances. In one 
instance, where plasmolysis had been quickly induced by means of a strong salt 
solution, two spheres of protoplasm occupied the two opposite pit depressions, from 
each of which a thread ran to the main protoplasmic mass. However, numerous 
experiments have convinced me that no reliance can be placed upon the results 
obtained by plasmolysis, as giving any certain clue to the existence of protoplasmic 
continuity. With this opinion Bower also agrees. | In fact, the greater proportion 
of threads bear no relation to pits, and in such an experiment as plasmolysing a hair 
of Primula sinensis, it is seen that as many threads go to the longitudinal as to the 
transverse walls, and are thus present on the free walls, as well as those separating 
contiguous cells (see also Plate 70, fig. 39). 
As I mentioned in the earlier part of my paper, my efforts to fix and stain these 
plasmolytic figures did not meet with perfect success, although picric acid gave very 
satisfactory results. I am, however, inclined to think that additional shrinking was 
produced by the use of glycerine, and the method deserves another trial. As a result 
of the staining, both the threads and the protoplasm were well brought into view, but 
a very great proportion of the threads were ruptured, and appeared as little spheres 
attached to the cell-wall. I was unable to trace the protoplasm into the cell-wall, but 
at that time I had not adopted my plan of staining with picric-HoFMANN’s-blue. It 
is possible that with this reagent some results may be obtained. In my paper before 
the Royal Society, § I stated that I had succeeded in showing the passage of the proto¬ 
plasm through the cell-wall when the wall was left intact, and not swollen by reagents ; 
the method consisting in treating thin sections of fresh material with saturated picric 
* See figure of cell of hair of Cucurbita , Sachs’ ‘ Vorlesungen,’ p. 752. 
+ Pringsheim, ‘ Uber Liclitwirkuug und Chlorophyllfunction.’ Leipzic, 1881. Tafel XIV., fig. 4. 
f Loc. cit. 
§ Loc. cit. 
5 R 2 
