Br. BealE; on the Red Blood-corpuscle, 
35 
Of the so-called cell-ivall. 
Next comes the important question concerning the exist- 
ence of a cell-wall. Although many observers have stated 
that there was no such structure in the red corpuscle^ others 
have brought forward evidence of its presence^ and the recent 
interesting and important observations of Dr. Roberts seem 
rather to confirm the view generally entertained as to the 
existence of such a structure.-^ 
I should remark that^ under certain circumstances^ there is 
no doubt whatever that the red corpuscle exhibits a dis- 
tinct outline^ and really consists of a membranous cell or 
envelope, closed at all points, with fluid contents ; but the real 
question to be decided is more than this matter of fact. Is 
the cell-wall, in those cases in which it has been observed, a 
real structural peculiarity, or does the appearance result from 
the condensation and chemical alteration of the outer part of 
the soft, red, viscid material of which the red blood-corpuscle 
is considered to consist, according to other views ? If red blood- 
corpuscles are immersed in various fluids, or even if allowed 
to remain for some time in serum, the outer part of the blood- 
t corpuscle does assume the appearance of a closed vesicle; and 
by the action of tannin, according to Dr. Roberts, the appear- 
ance as of tvfo membranes, one within the other, results. In 
blood-corpuscles which have been immersed in urine and most 
saline solutions, a very dark outline is produced, and granular 
matter, suspended, apparently, in a clear, colourless fluid, occu- 
pies the interior of the corpuscle. But these facts, and many 
others which might be adverted to, serve but to show that, 
under certain circumstances, the outer part of the material of 
which the blood- corpuscle is composed can be rendered inso- 
luble in water, and thus it is caused to present the appearance 
of a cell-wall. Many observers who maintain that a cell-wall 
is a structure necessary to the very existence of a cell, admit 
that the appearance of a membrane may also be produced 
artificially. Such an appearance can be readily produced in 
the case of cells,^^ or elementary parts after death, which cer- 
tainly have no such structure investing them during their 
life, and it can be produced in inanimate matter. It has 
been argued that, as bodies resembling these cells obtained 
from living structures, although altered by various methods of 
examination, can be produced artificially, all cells result from 
" Oh peculiar appearances exhibited by blood-corpuscles under the in- 
fluence of Solutions of Magenta and Tannin." ('Proc. Royal Society/ 
No. 55.) 
