ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
287 
It appears also to be a most excellent preservative for Crustacea and 
the higher orders of Arachnida ; and also for centipedes, but it has 
hitherto proved a failure for marine invertebrates in general. It must 
be remembered, however, that the perfect miscibility of the two liquids 
opens up endless possibilities. Its absolutely unevaporable nature 
makes it invaluable in a tropical climate, quite apart from its other 
qualities. 
With regard to this last remark I take the opportunity of stating 
that the acid enables coco-nut oil and turpentine to be mixed together. 
This forms a splendid microscopic fluid, in which objects may be 
allowed 1o soak without any previous preparation, and in which they 
become very transparent. A minute species of Crustacean, of the order 
Copepoda, and the leg of a fly, simply laid on a slide in a drop of this 
fluid and covered with an ordinary covering-glass, without any cell 
being made or cement employed, have lain on my table unaltered for 
the last ten months, and I cannot help thinking that such a medium as 
this cannot fail to prove a great boon to all workers with the Micro- 
scope.” 
Method of making Leaves transparent.* — Dr. A. C. Stokes writes, 
“ It frequently happens that the amateur microscopist would study the 
epidermal cells and appendages of the almost infinite variety of leaves, 
the structure of the cellular parenchyma, or body-substance of the leaf, 
the peculiarities of the cells and vessels of petals and of other parts of 
flowers. That is, he would if he could. It is sometimes an easy task 
to strip off the epidermis and to examine its cells, while in other cases 
it is almost impossible. Many chemical mixtures have been recom- 
mended for the purpose, and they accomplish the object after a fashion. 
The structure of the body of the leaf may be satisfactorily studied 
in sections, but not every microscopist can have a good microtome — 
a poor one is an abomination. There is also much to be learned and 
much beauty to be seen in the petals of flowers and in the cuticle and 
cells of the anthers, but it has been almost impossible to succeed 
here without special and somewhat complicated processes. Yet there 
is a way to make these objects either entirely transparent or suffi- 
ciently translucent to render their study pleasing and comparatively 
easy. The dealers will supply the microscopist with mounts of entiie 
flowers, made beautifully transparent, but the method of accomplishing 
this is not detailed with any spontaneity ; indeed the preparers, so 
far as I have been able to observe, are deaf and dumb when the 
subject is mentioned in their presence. I possess a fine slide of the 
entire flower of the common Houstonia, or “ innocence,” perfectly trans- 
parent, so that the cells of the epidermis, of the substance of the petals and 
of other parts, and the anthers with the pollen-grains in situ, may all be 
examined with a high power. How the thing was accomplished I have, 
until recently, been unable to ascertain. The secret has been so well 
kept that, so far as I can learn, only the dealers knew it ; the books 
have not discovered it. Yet by a very simple method these objects, as 
well as leaves, may be made entirely or almost transparent, so that 
the vessels and the cells may be studied at one’s leisure and in comfort. 
Microscope, xi. (1891) pp. 205-7. 
