820 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
commonly used ; and as I have devised one which I think has some 
advantages over his, I inclose yon a sketch of it, thinking it may interest 
some of your readers. Fig. 101 is an illustration of the clip in use as seen 
from above, and Fig. 102 is an end view of the same as seen from a section 
through the cover-glass. The clip should be made of rather stout 
springy wire, so as to grasp the slide firmly. This clip will be less 
liable to shift or become detached from the slide, and it has the 
advantage of being suitable for rectangular as well as circular cover- 
glasses.” 
Use of Gold Size.* — Mr. F. Disnett writes : — “ Gold size as a founda- 
tion ring for coloured cements answers much better than shellac in 
mounting insects whole or in parts, or other materials where a thick 
layer of balsam is needed. Much trouble is caused in finishing with 
alcoholic cements, because the alcohol softens the thin crust of hardened 
balsam at the edge of the cover, air-bubbles appear, and the same often 
happens again in finishing with coloured cements. The colours will 
run in and spoil the mount. All this is avoided with gold size. 
Another advantage is that in the final cleaning the last trace of balsam 
on cover or slip can be washed off with alcohol. Gold size answers 
much better than arabin in protecting the ring for cleaning with alcohol, 
as the latter has no affinity for it, and arabin is well known to be one of 
the strongest cements we have. Before putting on the foundation ring, 
mounts should be carefully examined, to see whether the balsam extends 
to the edge of the cover. Small cavities often exist where an air-bubble 
has made its final exit. The cement will inclose the air, the thin film 
will collapse and leave the balsam unprotected. Gold size is slow in 
drying, but if one builds a number of cells to-day, they will be exactly a 
month old a month from now, and in time will get as hard as glass. 
Make them with one or two, seldom three, successive coats, and always 
aim to have a lot of old cells on hand. When I wish to mount in one 
I put on a light coat of fresh gold size, drop in the glycerin, and dissect 
whatever it may be in the cell. I use 3/4-in. cells mostly, and as I 
disentangle and separate different structures I push them aside, and keep 
on till I have material enough to fill the cell. I arrange what I have as 
well as possible, fill up with glycerin, and cover. Lots of handling 
and transferring are done away with.” 
Laboratory Notes. — Mr. A. F. Stanley Kent writes to us : — 
(a) Farrcint’s Medium . — In making Farrant’s medium for a large 
class it is desirable to modify the usual mode of procedure. The 
following method I have found satisfactory. 
Make a solution with picked gum arabic to about the consistence 
of ordinary glycerin, mix it with an equal bulk of Price’s glycerin and 
place it in an ordinary plaited filter, a few pieces of glass rod being 
placed in the funnel to keep the paper from lying too closely against the 
glass. Now close the mouth of the funnel by means of a glass plate on 
which vaseline has been smeared, place a flask under the funnel so as to 
fit the neck, as closely as possible, and put the whole away for some 
weeks. A beautifully clear and bright solution will filter through into 
the flask. 
* The Microscope, x. (1890) pp. 281-2. 
