838 
MR. W. GARDINER ON THE CONTINUITY OF THE 
the latter instance the pit, as a whole, stains. In the former it is the staining of a 
substance other than pit membrane which runs through the latter, and which, by 
its different reactions, is to be separated from the pit membrane itself. Its reactions, 
as before-mentioned, point to a protoplasmic character. 
Experiments were made with other pulvini and other organs of similar character, 
the results of which are detailed below. The experiments were somewhat hurried as 
the season was late, and although, to the best of my belief, the results are accurate, 
yet I do not regard them as perfectly conclusive, and I must work over the subject in 
detail on a future occasion. 
Phciseolus nmltiforus appears to be connected as Amicia. 
Desmodium gyrans resembles Mimosa in structure. 
Dioncea muscipula. —Sections of the tissue next the vascular bundle showed the 
cells to be connected as in Mimosa. In the epidermal and sub-epidermal layers this 
structure was especially evident, and some processes were seen uniting the glands 
with the cells. 
Stamens of Cynara. —The lengthy oblong cells surrounding the central bundle 
appeared connected one to another principally through their end walls, in a manner 
almost exactly resembling that of a sieve tube. Apparently some connexion between 
them also took place through the side walls. 
Tendrils. —In the oblong cells of the tendrils of Bryonia, a similar sieve-tube-like 
arrangement appeared to occur, especially on the end walls. 
On the structure of endosperm cells. —From some points of view I could not regard 
the results I had obtained with pulvini as either perfectly satisfactory or perfectly 
conclusive. In spite of a probability little short of certainty, some doubt still 
remained; for it could be brought forward, that in the first place the results had been 
obtained by means of an extremely powerful reagent, with whose action we were by 
no means intimately acquainted ; and, secondly, that we had no such examples of the 
general perforation of the pit-membrane by protoplasmic threads. And even allowing 
that the pit-membrane was traversed by fine threads, the great question that required 
answering was—Do these threads in reality cross the middle lamella, or is it only a 
case of the membrane itself being pitted, and the threads running up to the lamella, 
but no further ? 
In order, therefore, to put my results on as firm a basis as possible, it was necessary 
to experiment with my methods upon any such cases as might exist, where the passage 
of protoplasmic threads through the cell-wall was a confirmed fact, or to endeavour to 
establish, in a manner which admitted of no doubt, other instances of the existence of 
similar phenomena. 
The first and most obvious examples of the occurrence of the perforation of the cell- 
wall are naturally afforded by sieve-tubes, and, in consequence, I began by investi¬ 
gating the results produced upon such structures by the reagents which I had 
employed in the case of pulvini. 
