288 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
By this treatment the liair-like and glandular appendages and stomata 
are preserved in place and in structure, the protoplasmic contents 
alone being contracted toward the centre of the cells. It is a method 
that I have stumbled on by accident, but one that I can recommend 
to the microscopical botanist that desires to examine these parts with- 
out destroying or disarranging any of the constituents. 
Place the petal, the anther, the whole blossom, or a part of a 
leaf on the slide, in a large drop of glycerin. See- that it is com- 
pdetely submerged beneath the liquid, and add a large cover-glass. 
It is best to use a slip without a cell. Then boil the glycerin over 
the lamp-flame until the parts are entirely transparent or at least trans- 
lucent, a condition that will arrive in a short time. Do not allow the 
boiling to be so violent as to disarrange the thin glass ; let it be so 
gentle that the bubbles will run one by one to the edge of the cover 
and there break. If the glycerin should become discoloured, as will 
often happen when leaves are under treatment, draw oil’ the liquid by 
a wet cloth and add fresh glycerin, repeating the process and the boiling 
until the leaf is saturated. The use of glycerin and the saturation of 
the cells form the secret of the process. The saturation is easily accom- 
plished with petals and similar delicate parts ; with thick and opaque 
leaves the time demanded is longer, and the specimen may become 
only translucent. I have made the thick and opaque leaf of the 
garden geranium, Pelargonium, so translucent that there was no 
difficulty in examining the hairs on the surface, the epidermal cells, 
the parenchyma and vessels, with the cells of the epidermis on the oppo- 
site surface. Of course there is a limit to the thickness and to the 
opacity that can be overcome, yet the method will be found exceedingly 
useful. Leaves and petals do not entirely lose their colour, although 
they become beautifully transparent. Of course the specimens must be 
permanently preserved in glycerin. 
The secret that the dealers have seemed to keep so carefully, and 
that the books have ignored because apparently their authors had not 
learned the process, is here placed at the reader’s disposal. I am sure 
that he will be pleased with the result of his experiment, and that he 
will find the objects so often mentioned, rendered easy of examination. 
Petals and other parts of the flower need no previous preparation. It is 
well, however, to cut the leaves so that there shall be two or more open 
surfaces for the penetration of the glycerin. In some very delicate 
specimens this will not be necessary ; it is so when the leaf is thick or 
very opaque.” 
Preparing Agarics.* — M. Fayod says that the best way to preserve 
specimens of agarics intended for microscopical examination is to let 
them dry slowly. The best way to do this is to place them in paper 
capsules and then to inclose them in cardboard boxes. 
Such specimens when ready are to be cut dry. The sections 
are placed in water containing a little ammonia, if the filaments be 
thick-walled, and in strong ammonia or dilute potash if the wall be 
thin. 
The specimens may also be preserved in spirit, and the spirit may 
* Anu. Sci. Nat., ix. (1S89). See fiev. Gen. de Bot., iii. (1891) pp. 427-8. 
