64 
INTERCELLULAR RELATIONS OF PROTOPLASTS. 
adhering by a part of its periphery to the cell-wall. Its free 
margin, that is, the boundary of its external differentiated 
layer, the ectoplasm, he describes as of smooth unbroken 
outline. On removal of the salt by pure water the protoplasm 
will, sometimes even after several days remaining in the 
plasmolysed state, gradually reabsorb, and resume its old 
place applied to the cell-wall. 
Apart from the previously known cases mentioned above, 
and the striking phenomena uniformly present in many 
tissues, which will be illustrated in a subsequent section of 
this paper, the light which has within the last two years been 
thrown on the actual origin of the cell-wall would in itself 
predispose to doubt on the subject of this apparent freedom of 
the cell-wall from firm attachment to the protoplasm whence 
it derives its origin. The theory of intussusception, as 
accounting for the growth in extent and thickness of the cell- 
wall, has, in the opinion of most physiological botanists, to be 
more or less completely abandoned in favour of the older 
theory of apposition, now reaffirmed by Schimper, Meyer, 
Strasburger, Schmitz, von Hohnel, and others. The position 
especially maintained by Strasburger * and Schmitz,! that 
the cell-wall is formed and thickened by protoplasmic 
granules, called by the latter microsomcita ; and the opinion 
expressed by the former (1. c., p. 174) that cellulose is formed 
by the direct splitting of protoplasm,! greatly enhance the 
interest of this question. We cannot help asking ourselves 
(1) Do any of the protoplasmic threads which connect the 
poles of nuclei in process of division, and in (or on) which the 
elements of the cell-plate are formed, persist after the forma¬ 
tion of the partition wall ? and (2) If the microsomata more 
or less bodily pass over into the substance of the cell-wall, is 
there thereby established a more intimate subsequent con¬ 
nection than de Vries’ researches would suggest between 
cell-wall and protoplasm ? 
An interesting contribution to the knowledge of the 
relations between the cell-wall and the protoplasm it 
encloses, as illustrated in the phenomena of Plasmolysis, 
* Strasburger, “ Ueber den Bau und das Wachsthum der Zell- 
haute,” 1882. 
f Schmitz, “ Sitzbr. der niederrh. Gesell. fur Natur-und Heilkunde 
in Bonn,” 6th Dec., 1880. 
f “ Die Beobachtungen iiber Scheidewandbildung zeigen aber, 
sobald die Natur der Zellplattenelemente als Mikrosomen erkannt 
ist, auf das Bestimmteste die Bildung der Cellulose durch directs 
Spaltung des Protoplasma,” 
