CELLULAR STRUCTURE OF THE RED BLOOD-CORPUSCLES. 41 
cover. In order to prevent the development of Bacteria, 
about two fluid drachms of carbolic acid solution were added, 
and the mixture kept covered in a room of ordinary tempe¬ 
rature for four weeks, at the end of which time the delicate 
colourless spheres were still distinctly visible, although they 
had a little further diminished in size, only measuring about 
-j -pV o-th of an inch across. 
From these various observations, it appears that human 
red blood-corpuscles are composed of two different ingre¬ 
dients, the one haemato-crystallin, of a crimson colour, and 
dissolving freely in water, the other of a whitish hue, and 
insoluble in water, even on prolonged maceration; but so 
minute are the blood disks in mammalia generally, that it is 
extremely difficult to determine the exact relation of these 
constituents to each other. It occurred to me, however, that 
investigations upon the large blood-globules of reptiles might 
be more successful, and after numerous disappointments I pro¬ 
cured, in November last, from a former patient near my late 
residence on Cayuga Lake, in Western New York, two spe¬ 
cimens of the Menobranchus or Proteus, whose red blood 
disks, as far as known, with a single exception, exceed those 
of all other animals in magnitude, measuring about ^-^th of 
an inch in length by -g-E-o^h- of an inch in breadth, and actually 
visible, in a strong light, to the naked eye of a myopic person 
like myself. The gigantic corpuscles being about six times 
the diameter, and consequently 216 times the magnitude of 
those of man, evidently afford much better opportunities for 
the detection of their membranous parietes, if such exist; 
and in addition to this great advantage, I discovered, quite 
unexpectedly, in the course of my experiments upon them, 
that their coloured portion possessed the remarkable pro¬ 
perty of crystallizing with great readiness within its envelope, 
and so enabling us to analyse, as it were, the corpuscles, by 
furnishing a singularly positive demonstration of the exist¬ 
ence of a cell wall, totally distinct from the cell contents 
which undergo crystallization. These crystals, as often 
happens with those produced in the presence of organic 
matter, are frequently irregular, but their typical form appears 
to be that of a quadrangular prism, with dihedral summits, 
the angles sometimes being truncated. They may be easily 
prepared, as I have now done at least fifty times, by deposit¬ 
ing a drop of blood Trom the Menobranchus upon a slide, 
allowing it to remain uncovered about ten minutes, or until a 
mere line of desiccation appears at the margin, and then 
covering it with a thin glass; on examination with a power 
of 200 diameters, numerous corpuscles along the edge of the 
