IV. On the continuity of tlie protoplasm through the walls of vegetable cells. 67 
;ads may 
sxamples 
;h power 
s micros- 
ned area 
ano, and 
pearance 
structure 
the pe- 
spheroid 
the like. 
ent afler 
. 
a sieve- 
vvhereby 
oplasmic 
n of the 
•lod., at 
vinus of 
as lo llio 
s limited 
displays 
ti clearer 
o neigh- 
ition. In 
of stria- 
irea. In 
lining of 
•ity wilh 
iS in the 
in to the 
iraue. 
to stick 
bited by 
ley stick 
xislence 
itoplasrn 
brought 
ry great 
i'd by tlio 
number of cases seldom oeenrs at the closing membrane itself, but nearly 
always, on one or on both sides of this point. 
In Robinia in the same way the processes from the main protoplasmic 
mass are verv attenuated, although thev do not appear as tense as those of 
Mimosa, neither is the appearance of direct continuity so often visible. At 
the same time however the apices of the processes do not contract avvav 
from the pit-closing-membraue, but abut on to, and are placed in connection 
with each other, by means of, the striated, stained, and flattened sphere-like 
structure, of vvhich I have so often spoken. 
In Amicia on the other hand, the processes usually contract away very 
appreciably from the closing membrane, so that between this stained struc¬ 
ture, and the more deeply coloured processes, a very considerable space 
may intervene, while in Phaseolus by the inost careful preparalion it is 
almost impossible to obtain sections which demonstrate that the processes 
entering the pits, bear any intimate relation to the pit-closing-membrane. 
1 may remark that these phenomena bear no direct relation to the degree 
of development of the pits, for the pitting which occurs in Amicict, for in- 
stance is much more pronounced than that of either of the other three.') 
In the prosenchyma cells surrounding the vascular bündle, the processes 
entering the pits appear always to contract away from the pit-membrane, 
but between the two processes the same stained area occurs as in the 
parenchyma cells. 
In the organ of movement of Desmodium gyrans, I have but little doubt 
that the same structure prevails as in Mimosa, but on account of the extre- 
melv small size of the cells, and of the tissue in general I have been unable 
to make any definite observations. 
A detailed examination of the leaf of Dionaea muscipula showed that 
in the parenchyrnatous cells there was an actual continuity, and the pit 
processes entering the pits clung to the closing membranes as in Mimosa. 
In the epidermal cells I could not observe that such was the case. 
The walls of the cells of the secreting glands vvhich abut on to the 
general tissue of the leaf are freely pitted, and it seeined to me that in some 
instances 1 could detect the existence of a continuity between them and the 
cells of the leaf parenchyma, but here again I can as yet make no positive 
Statement. In the parenchyrnatous tissue of the stamens of Berberis, I could 
detect a definite colouring of the pit-closing-membrane. In the stamens of 
Centaurea and Cynara the cells are full of protoplasm, and exhibit little if 
any vacuolation. After trealment with Sulphuric acid, great contraction of 
the protoplasm occurs, and in any two adjacent cells, the protoplasm in 
contracting from the transverse walls, and also from certain areas on the 
1) It is of great interest to note that the degree of tenacity with which the proto¬ 
plasmic processes cling to the pits is in direct relation lo their degree of sensitiveness. 
;ads may 
sxamples 
;h pow r er 
s micros- 
ned area 
ane, and 
pearance 
structure 
the pe- 
spheroid 
the like. 
ent afler 
. 
a sieve- 
whereby 
oplasmic 
n of the 
•lod., at 
vinus of 
as lo llio 
s limited 
displays 
ti clearer 
o neigh- 
ition. In 
of stria- 
irea. In 
lining of 
•ity with 
is in the 
in to the 
iraue. 
to stick 
bited by 
ley stick 
xislence 
itoplasrn 
brought 
ry great 
i'd by the 
5 
