148 
NOTES AND MEMORANDA. 
(c) a threadwork of fine fibres surrounding tbe primary bundles, in 
mesbes. 
13. Examination of connective tissue, in various stages of inflam- 
mation, yields strongly confirmatory evidence in favour of tbe inter- 
pretation given by tbe author to tbe appearances above described. 
Lymphatics of the Choroid and Retina . — Tbe ‘Lancet’ (July 10) 
says that tbis subject bas been recently investigated by Morano. He 
last year announced tbe discovery of minute perivascular lymphatic 
channels in tbe choroid, communicating with the perisclerotic space, 
and penetrating to the chorio capillaris ; and be bas now ascertained tbe 
presence of stomata in tbe pigment layer of tbe retina (formerly called 
“ choroidal epithelium ” similar to tbe stomata described by Reckling- 
bausen in tbe serous membranes. These retinal stomata are best 
marked in tbe frog, and are mostly formed by tbe separation of three 
or four of tbe epithelial cells ; they present internally a curious 
valvular arrangement due to the presence of three or more small 
processes from tbe sides of tbe orifice, and covered by a delicate endo- 
thelium. In mammals they are less constant, and may be destitute 
of valves, if present. 
NOTES AND MEMORANDA. 
Preparing Sections of Coal. — Dr. C. Johnson gives tbe following 
as tbe method adopted by him in preparing sections of coal, in the 
‘Cincinnati Medical News’ (July, 1875): — 1. Macerate suitable 
pieces, jor| 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 tbe 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 tbe 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 tbe label. 
A Mode of Counting the White and Red Blood-corpuscles. — 
Tbe ‘Medical Times and Gazette’ (August 14) gives tbe following 
account of M. Malassez’s mode of counting tbe number of corpuscles 
in blood : “ He draws tbe blood into a peculiar kind of pipette, in 
which be dilutes it with a hundred parts of an indifferent liquid, so 
that its constituents may be as equally distributed as possible. Tbe 
liquid be 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 
