148 
NOTES AND MEMORANDA. 
(c) a thread work of fine fibres surrounding the primary bundles, in 
meshes. 
13. Examination of connective tissue, in various stages of inflam- 
mation, yields strongly confirmatory evidence in favour of the inter- 
pretation given by the author to the appearances above described. 
Lymphatics of the Choroid and Betina. — The 'Lancet' (July 10) 
says that this subject has been recently investigated by Morano. He 
last year announced the discovery of minute perivascular lymphatic 
channels in the choroid, communicating with the perisclerotic space, 
and penetrating to the chorio capillaris ; and he has now ascertained the 
presence of stomata in the pigment layer of the retina (formerly called 
" choroidal epithelium" similar to the stomata described by Eeckling- 
hausen in the serous membranes. These retinal stomata are best 
marked in the frog, and are mostly formed by the separation of three 
or four of the epithelial cells ; they present internally a curious 
valvular arrangement due to the presence of three or more small 
processes from the sides of the orifice, and covered by a delicate endo- 
thelium. In mammals they are less constant, and may be destitute 
of valves, if present. 
NOTES AND MEMOEANDA. 
Preparing Sections of Coal. — Dr. C. Johnson gives the following 
as the method adopted by him in preparing sections of coal, in the 
* Cincinnati Medical News ' (July, 1875) : — 1. Macerate suitable 
pieces, J or J inch thick, in liquor potassa until they swell and soften. 
2. Soak for a few hours in pure water, and drain. 3. Macerate in 
nitric acid until the colour changes from black to brown. 4. Soak 
for a few hours in water, and drain. 5. Put aside in alcohol for a 
day or two. If for future use, let the pieces remain in alcohol. 
6. Fasten in a cutter with paraffin, and make sections. 7. Place in 
absolute alcohol. 8. In oil of cloves. 9. In balsam; and 10. Set 
aside with a small weight or cover, having, before the mounting, 
attached the label. 
A Mode of Counting the White and Red Blood-corpuscles. — 
The 'Medical Times and Gazette' (August 14) gives the following 
account of M. Malassez's mode of counting the number of corpuscles 
in blood : " He draws the blood into a peculiar kind of pipette, in 
which he dilutes it with a hundred parts of an indifferent liquid, so 
that its constituents may be as equally distributed as possible. The 
liquid he uses consists of one volume of a solution of gum of specific 
gravity 1020, and three volumes of a solution containing equal parts 
of sodic sulphate and sodium chloride, also of specific gravity 1020, 
to which one drop of a concentrated solution of sodic carbonate may 
be added. The diluted blood is transferred from the pipette into a 
fine capillary tube of elliptical section, whose dimensions are accu- 
rately known ; this is brought directly under the object-glass of the 
