CELLULAR STRUCTURE OF THE RED BLOQD-CORPUSCLES. 43 
lie in favorable positions, may include almost all the coloured 
portion of the corpuscle, without in the least affecting the 
contour of its cell wall. 
I regret exceedingly that the difficulty of obtaining and 
preserving the Menobranchus alive has prevented me from 
attempting to exhibit specimens of its fresh blood; but in 
the hope that other microscopists w r ill repeat and correct or 
confirm my researches upon it, I am desirous of recording 
them and the conclusion which they seem to involve. 
After a great many attempts, on which I spent altogether 
about eight hours J steady work, I have twice succeeded in 
cutting a corpuscle in two with sharpened needles upon a 
stage of the microscope, and beneath a half-inch objective, 
combined with a No. 2 eye-piece. On penetrating the 
vesicle with the edge of the needle, its coloured contents 
were instantly evacuated, and disappeared at once in the sur¬ 
rounding fluid, while the cell wall immediately shrunk toge¬ 
ther, and became twisted upon itself and around the nucleus 
into a perfectly hyaline particle, which showed some ten¬ 
dency to adhere to the point of the instrument. It would 
therefore seem that the haemato-crystallin was neither viscid 
nor semi-solid, and that the cell wall was structureless, and 
possessed only moderate tenacity, but of course the obser¬ 
vations were too few in number to be accepted as conclusive. 
When the corpuscles remained for two or three hours under 
observation, those which did not crystallise often showed the 
wrinkled appearance figured by Hassal in his Illustrations, 
and described by Rollett, in Stricker^s f Handbuch der Lehre 
von den Gew'eben/ Zweite Liefrung, S. 286, and which seemed 
to me due to the tendency of their colourless envelope, as 
the contained haemato-crystallin condensed around the nucleus, 
to accommodate itself to the diminished contents of the cell 
by falling into folds frequently ramifying from the nuclear 
centre. When pressure was made by means of a mounted 
needle upon the covering glass, almost directly over a red 
disk, whose contents had undergone this contraction, the 
first effect was to round out the contour of the corpuscle, and 
unfold the creases in its walls, the globule behaving as you 
might expect a bladder half full of water to do if you stepped 
firmly upon its centre ; on continuing the process, however, no 
rupture of the walls could be detected, the contained fluid 
appearing to rapidly transude through its former envelope, 
which, on the needle being removed, collapsed to perhaps 
half its former size, and presented the aspect of a loose bag, 
almost without coloured contents, surrounding the nucleus. 
These changes were also examined under the ¥ ' T -inch objec- 
