150 Detection of Bed and White [^CmLl STiff 
treacle, composed of hgemato-crystallin," and wMe admitting that 
the outer part of each mass may be of firmer consistence than the 
interior, denies that in mammaha generally they possess a true cell- 
wall, so that, if his doctrine be correct, the chance of detecting any 
isolated red corpuscles in a mass of blood clot, howsoever moistened, 
seems almost as hopeless as the search after individual rain-drops in 
a cake of melting ice. 
In the progress of some researches upon the distension of the 
white blood-cells when acted upon by water,* I have often inci- 
dentally noticed that many of the red corpuscles become, after a 
time, so transparent and colourless by the solution and abstraction 
of their " haemato-crystallin," that they are quite invisible under a 
power of 400 diameters, and appear to be in reality dissolved as 
stated by Prof. Wyman, M. Ch. Kobin, and other authorities ; yet 
when closely scrutinized under a immersion objective, their faint 
transparent outlines can still be detected, thus confirming Prof. 
Beale's assertion t that " with the highest powers not only do we 
meet with extremely minute corpuscles, but many of them are so 
very transparent that they could not be seen at all under a low 
power. Extremely transparent bodies are demonstrated under 
high powers, which would certainly be passed over by those in 
ordinary use." 
This observation appeared to have such an important bearing 
upon the subject of my present paper that I entered upon its 
special investigation, which I propose briefly to detail, promising 
that while the results seem to prove a very marked difterence in 
density, if not in constitution, between the external and internal 
portions of the blood discs, I do not consider the data here collected 
sufficient for controverting the opinions of those experienced histo- 
logists who deny to the red corpuscle a proper cell-wall. 
Expt. 1. — Five drops of blood drawn with a cataract needle 
from the tip of the finger was stirred with half a fluid-ounce of 
river-water in a conical wine-glass, which was carefully closed 
against the entrance of extraneous matters and set aside. Twenty- 
four hours after a scanty sediment, whitish in colour, was visible in 
the bottom of the vessel, and a small portion of this deposit ex- 
amined under the showed that it was chiefly composed of red 
blood discs, exhibiting no appearance of rupture, globular in form, 
quite colourless, and so transparent that very close attention was 
necessary for their detection. Similar results were obtained at the 
end of forty-eight hours, but at the end of seventy-two hours many 
of these globules were obscured by the formation of Vibriones and 
Bacteria, which were developing with great rapidity. 
Expt. 2. — A thin film of human blood was spread out upon a 
slide, allowed to dry, covered with thin glass, and then adjusted 
under the ^-^ ; after finding a suitable field which contained a white 
* ' Pennyslvania Hospital Keports,' 1869. t Op. cit,, p. 170. 
