Researches into the Anatomy of Plants. 279 
I\find other intervals also between the cellules, which 
may be called intercellulary canals (ductus intercellulares). 
They descend in a perpendicular direction; they are not 
visibly in communication with the intervals which I have 
described, and they contain a peculiar juice, which is less 
fluid than the sap, and which issues sometimes in the form 
of small round corpuscles, and sometimes in the form of 
crystals. These canals are much larger than the meatus 
intercellulares. Wide in PI. I. fig. 4. letter a, these inter- 
vals in a longitudinal section of the same stalk. They 
exist in many plants, particularly if the cellular texture is a 
little serrated ; and we may class them among the reservoirs 
of the sap, which I shall presently mention. 
In the ferns and the mosses, the intervals are so great, 
and so well united together, that they perfectly resemble 
vessels, They form a network, of which the meshes are 
cellules, It is highly probable that Hedwig, who laboured 
hard at the theory of the mosses, was so deceived by this 
net-work, as to form a separate kind of vessels which he 
called vasa revehentia. 1 have represented a similar net- 
work taken from the scales (strige) of the scolopendrium 
vulgare, Pl. I. fig. 6. These scales are remarkable, because 
the intervals are of a colour different from that of the cel- 
lules, and they furnish an indubitable proof of the existence 
of the intervals. 
M. Mirbel compares the cellular texture to the froth of 
common soap. This comparison is very correct, and I do 
not know a better. But the author rejects entirely the 
double partitions, which does not agree with this compari- 
son; for the froth of soap is composed of bubbles of air, 
separated originally from each other, so that each bubble is 
formed as it were of a distinct membrane, and it is only by 
meeting that these partitions are confounded. Frequently, 
the isolated bubbles rise to the surface of the froth, as is 
the case with cellules isolated in the cavities of the peduncle, 
the,receptacle of the flowers, and of the fruit. I am even 
of opinion that the cellules have had the same origin with 
the bubbles alluded to; that a gas has been developed in a 
viscous fluid, and has reduced it into small vesicles, which 
have approached each other. As the vesicles of the cellular 
texture have a more regular arrangement than the soap 
b ubbles,a peculiar attraction, necessary to the increase of 
the vegetable, must have forced them into this arrangement. 
According to M. Sprengel, the cellular texture derives its 
origin from small grains which we find in the cellules a 
S4 the 
