SCIENTIFIC SUMMARY, 
213 
aniline dye. At the operator’s pleasure, the chlorinated leaves may he 
soaked in pure water for an hour, and afterwards in a 3 per cent, aqueous 
solution of alum, in preparation for the logwood staining. If the aniline blue 
dye be chosen, let the acidulated leaves be immersed in the blue fluid, and 
soaked for twenty or thirty minutes. Upon being withdrawn their colour 
will be found to be very intense, but washing in 90 per cent, alcohol for half 
a minute will remove superfluous aniline, and a final bath in absolute alcohol 
will in a few minutes prepare the object for being soaked in oil of cloves. 
With a bent platinum spatula the transparent preparations must be laid 
upon a slide, receive a liberal quantity of a solution of old balsam in chloro- 
form poured upon it, and be covered with thin glass, on which a small 
weight is to be placed. In the course of a month or two the excess of 
balsam may be cleaned ofi, but the slide should bear a provisional label 
before the specimen is mounted.” 
The Examination of Blood-corpuscles . — The ordinary method of soaking 
out the shrivelled and distorted cells from a dried blood stain or clot, and 
then measuring their diameter under a suitably high power, is conceded to 
be satisfactory in many of the most frequently occurring cases (for instance, 
Dr. J. G. Richardson, U.S.A., who has been for several years a prominent 
advocate of the reliability of this method of distinguishing human blood, 
under high powers from that of certain domestic animals, has recently shown 
by numereus experiments the feasibility of thus distinguishing the blood of 
man, ox, and sheep) $ but it fails when the corpuscles approach each other 
too nearly in size. It also (says the “ American Naturalist,” February) 
gives unsatisfactory results with the oval nucleated corpuscles of reptiles, 
&c., which, when swelled by soaking, do not arrive at their original con- 
dition. Dr. R. M. Bertolet, of the Philadelphia Hospital, is represented as 
advising the following method of staining these corpuscles, which is ap- 
plying one of the chemical tests for blood in a new way and with great 
precision. The blood is moistened with slightly acidulated glycerine, and 
then carefully irrigated with an alcoholic solution of guiacum resin, and 
finally a small quantity of ethereal solution of ozonic ether (peroxide of 
hydrogen) is flowed beneath the cover. By this procedure the whole 
corpuscle is stained of a uniform colour, which varies in different corpuscles 
from a light sapphire to a deep blue, except in case of the nucleated cor- 
puscles in which the nucleus assume a distinctly different tint from the rest. 
American Opinion of Boss's Microscopes . — We had imagined that the 
“ American Naturalist” had extremely American prejudices, but it seeina 
we are entirely mistaken, as the following observations, taken from its 
number for February 1875, will show : — “ The adoption by this great house 
of the Jackson model of stand (which has long been very generally pre- 
ferred in this country, if not everywhere), in place of the transverse bar 
model which had come to be familiarly known as the Ross style, is an 
innovation of sufficient importance to attract special notice, and, we may 
add, congratulation. The magnificent workmanship of the old Ross stand 
is no secret, and is a sufficient assurance of the mechanical excellence of the 
new ones, while the fact that they are designed by Mr. Wenham leaves 
nothing to be said as to their microscopical efficiency. The new stands, 
while adhering substantially to the Jackson model, combine some of the 
