852 
MR. W. GARDINER ON THE CONTINUITY OF THE 
in families of that order, that differ but little one from another. Russow’s results 
are also of especial value here. 
Results with Plasmolysis. —At an early stage in this investigation certain pheno¬ 
mena in connexion with experiments upon the preservation of tissues forced 
themselves upon my notice. What was especially striking was the different result 
which was obtained when different tissues were treated with the same reagent, and 
under the same conditions. 
Thus, upon examination of sections of the pulvini of Mimosa, Robinia, and Amicia, 
which had been all carefully preserved in absolute alcohol, it will be seen that the 
degree with which the protoplasm is contracted from the cell-wall varies greatly in 
the three cases. In the cells of Mimosa the protoplasm will have undergone bat 
little contraction, and the whole tissue will show signs of successful preservation. In 
Robinia, on the other hand, an appreciable contraction has evidently taken place, and 
in Amicia this state of things has attained a maximum, for almost every cell exhibits 
the much shrunken protoplasm lying freely in the cell cavity, and separated on all 
sides from the cell-wall. Since in every instance the cells are full grown, and are 
under equal conditions, it would seem probable that the protoplasm is held closer to 
the cell-wall in some cases than in others. 
After having obtained my results with Mimosa, Robinia, and Amicia, it seemed the 
more probable that the above appearances were in reality a consequence of the 
intimate union between the cell-wall and protoplasm which my investigations had 
shown to exist, and the pronouncedness of which appeared to vary. 
In consequence of these and other considerations, I was led to study, in a detailed 
manner, the effect of plasmolysing such cells, since it seemed to be almost certain 
that the phenomena accompanying such a condition would afford additional con¬ 
firmation of the results I had already obtained with somewhat powerful reagents.* 
According to De Vries t when the plasmolytic condition is induced in a cell by means 
of dilute dehydrating agents, the protoplasm (primordial utricle) separates entirely 
from the cell-wall, and appears as a much contracted vesicle lying freely in the 
cell cavity. 
On the other hand, both Pringsheim J and Nageli § had noticed that in certain 
cases the protoplasm appears to separate with some difficulty from the cell-wall, and 
that it was frequently connected to it by means of one or more threads in those cases 
where great contraction had taken place. 
It had also been long known that in filamentous Algce, || the protoplasm upon 
contraction is often connected to the cell-wall by threads. These, however, may 
be rather described as isolated cases, for no generalisations were made, nor was any 
* Proc. Hoy. Soc., Nov. II, 1882. 
f ‘Untersuchungen iiber die Meckaniscken Ursacken der Zellstrekung.’ Leipzic, 1877. 
+ ‘ Bau. und Bildung der Pflanzenzelle.’ 1854. 
§ ‘ Pflanzenpkysiologiske Untersuck.’ 1855. 
|| Hofmeisteb, ‘ Die Pflanzenzelle.’ 1867. 
