CELLULAR STRUCTURE OF THE RED BLOOD-CORPUSCLES. 45 
rents beneath the cover by tapping the latter with a mounted 
needle. On changing the direction of these currents so as 
to strike the disk upon various parts of its surface in succes¬ 
sion, I was enabled to satisfy myself conclusively that it pos¬ 
sessed a bladder-like cell wall, perfectly flexible (now that it 
was no longer distended wflth hsemato-crystallin), and capable 
of being dimpled in, as it were, by the force of the current 
impinging upon any side until it applied itself accurately to 
the subjacent surface of the nucleus, thus furnishing strong 
evidence against the doctrine of a sponge-like stroma (or 
oikoid), as taught by Briicke and Strieker, being a constituent 
of the red blood-corpuscle. 
If water was allowed to flow in upon a specimen whose 
disks had undergone the curious crystallization above de¬ 
scribed, diluted liquor sanguinis seemed to rapidly enter the 
corpuscles, by endosmosis, and dissolved the contained crystals 
which generally assumed a foliaceous appearance, such as we 
often see crystals of triple phosphate put on when macerated 
in alkaline urine. As the haemato-crystallin dissolved, the 
natural colour of the corpuscle was restored; its walls, if 
they had been previously propped out upon the points of the 
crystals, reassumed their normal shape, and in some in¬ 
stances these shortened or broken crystals were observed 
to move freely in the cavity between the nucleus and the 
cell wall. 
Before attempting to make any deduction from the above 
experiments upon the blood of the Menobranchus, it may 
not be amiss to refer briefly to the views entertained by most 
German writers in regard to the red blood-corpuscle. Ac¬ 
cording to Rollett, in Strieker's 4 Handbuch' above referred 
to, p. 296, Henson was led, from the apparent retraction of 
the cell contents from the membrane as seen in the blood- 
corpuscles of reptiles, to ascribe to the red disks a protoplasm 
which, accumulated especially around the nucleus and over 
the inner surface of the envelope, was bound together by 
delicate radiating crossed threads, and in its intestines con¬ 
tained the coloured liquid cell contents (getarbte zellfliis- 
sigkeit) ; but in the opinion of Rollett, this thing is unte¬ 
nable in view of the knowledge we have lately obtained in 
regard to the properties of protoplasm, from the researches 
of Max Schultze and Kiihne. 
Briicke, who has observed these appearances after the 
action of a 2 per cent, boric acid solution, pictures to himself 
in explanation thereof, in the first place, “a porous form 
element, consisting of a motionless, very soft, colourless, and 
perfectly transparent substance; further, he represents to 
