822 
MR. W. GARDINER ON THE CONTINUITY OF THE 
and the permeability and peculiar characteristics of the cell-wall in question must be 
taken into consideration; the difference of reaction being in different cases very great. 
If, however, the action be properly regulated, the cell-wall will be much swollen; the 
protoplasm will undergo a certain amount of contraction, but, at the same time, will 
not be withdrawn from the cell wall at those points where any intimate union exists 
between the wall and the protoplasm. The middle lamella will, of course, not be 
destroyed. If the action be allowed to proceed further, the protoplasm itself will be 
attacked, the cell-wall will begin to dissolve, the middle lamella will also swell ; and 
when in this condition will stain very deeply with reagents, thus making any 
satisfactory observation impossible. 
Experiment shows that unless the action is decidedly forced, the cell wall, though 
apparently dissolved, does not in reality undergo complete solution, but is only 
swollen and diffluent. That this is the case may be proved by treating a washed out 
section with Chlor. Zinc Iod., when the ordinary blue cellulose reaction will be obtained. 
The probable action of the sulphuric acid upon sections of the fresh material may now 
be dealt with. In the first place, the protoplasm is apparently at once killed, although, 
at the same time, decided shrinking occurs, owing to the great dehydrating power of 
the reagent. This shrunken appearance is, however, somewhat magnified, because, in 
addition to the contraction produced by the rapid abstraction of water, the protoplasm 
has also been squeezed and pressed upon, on all sides, by the swelling cell-wall. But 
the point which must be especially strongly brought into prominence, is the fact that 
during the swelling any close relation which may exist between the protoplasm and 
the cell-wall appears to be maintained, at least where such relation is at all pronounced. 
Thus in cases where reactions with Chlor. Zinc Iod. and iodine show that the closing 
membrane of a pitted cell is perforated by fine protoplasmic threads, it will be found 
that when such a cell is treated with sulphuric acid, the protoplasm projecting into 
the pit, and especially that portion of it abutting on to the closing membrane, will 
firmly adhere to the latter, and will resist, without rupturing, a very considerable 
strain ; and even if rupture should at length take place, it will seldom, if ever, occur 
close to the pit membrane. In attempting to explain the appearances produced by 
the action of strong sulphuric acid, one must clearly bear in mind that there are 
two factors to be considered, viz.: the role of the protoplasm and the role of the cell 
wall. At the same time there is going on, not only a shrinking of the one, but a 
swelling of the other. Two principal objections may be very reasonably brought 
forward to explain the fact, that the protoplasm adheres to the pit. First, it may be 
said, that the protoplasm is retained and even injected into the pit by the pressure of 
the swelling wall. That this objection will not hold is apparent from the fact that the 
same phenomenon occurs in the case of cells which have been cut into. Furthermore, 
the swollen wall frequently does not abut directly on to the protoplasm, but a con¬ 
siderable space intervenes between the two. Again, by the action of strong 
