^Jou?ml,^uTy!!T869^T PROaRESS OF MICROSCOPICAL SCIENCE. 51 
The Sleep of Plants is hardly a histologic paper, but we call atten- 
tion to it, as it may interest our readers. It is by M. Cli. Royer, in 
the Botanical Section of the last Annales des Sciences Naturelles, May. 
Brunetti's Process for preparing Anatomical Specimens. — Brunetti's 
process has this advantage over some others (such as those of Gorini 
and Segato), that it is adapted to specimens intended for microscopical 
examination. The following is an account of the process. It consists 
of four stages, namely, washing, divesting of fat, treating with tannin, 
and desiccation. A stream of pure water is injected through the blood- 
vessels and secretory ducts of the part to be preserved ; the water is 
afterwards expelled by means of alcohol. To remove the fat, the 
vessels are in like manner injected with ether, which penetrates the 
tissues and dissolves all the fatty matters. These operations occupy 
a couple of hours, and the object thus prepared may then be kept for a 
long time in ether if desired. A solution of tannin in distilled water 
is next injected in a similar manner, and the ether washed out by a 
stream of pure water. The desiccation is accomplished as follows : — 
The preparation is placed in a double-bottomed vessel containing 
boiling water — a sort of hain marie — in order to displace the fluid 
previously used by dry, heated air. Air compressed in a reservoir to 
about two atmospheres is forced into the vessels and ducts through 
heated tubes containing chloride of calcium; all moisture is thus 
expelled and the process is completed. The preparation thus treated 
is light, and retains its volume, its normal consistence, and all its 
histological elements. The most delicate sections may be practised 
in any direction, and accurate observations made with the microscope. 
The relative position of the organs and tissues being preserved, much 
better opportunities for pathologico-anatomical demonstration are 
afforded than by the former inadequate method of preservation in 
alcohol. The blood being expelled, pathological coloration is alone 
perceptible. 
A New Process for Photomicrography. — M. Bourmans has described 
(Les Mondes, May 27th) a method which, though it has some imper- 
fections, may be found useful. It is described and somewhat severely 
criticized in the ' British Journal of Photography,' from whose pages 
we take the following description : — " The plan consists in employing 
an ordinary microscope having a mirror fixed in the tube between the 
eyepiece and the object-glass of the instrument. This mirror is lightly- 
silvered glass, and the light reflected from its surface is thrown out 
of the instrument laterally, and at a right angle to the course of the 
rays leaving the object-glass. The rays so deflected from their ordi- 
nary path pass on and are received on a focussing-glass or on the 
sensitive plate. But the mirror, while reflecting a large proportion of 
the rays, transmits, according to M. Bourmans, about 25 per cent, 
of the total light which it receives, and the rays so transmitted pass 
on to the eyepiece of the instrument and finally reach the eye of the 
observer. When an object has to be photographed, it is suitably 
placed on the stage of the microscope, and viewed in the ordinary 
way through the eyepiece of the instrument. It can then be accu- 
rately focussed by means of the small amount of light passing through 
the mirror. Having placed the sensitive plate in its carrier, but pro- 
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