OUTLINES OF BOTANY. 
XXXUl 
it, and the sooner the plants will dry. The paper ought to be coarse, stout, and un- 
sized. Common blotting-paper is much too tender. 
236. Care must be taken that the paper used is well dried. If it be likewise hot, 
all the better ; but it must then be very dry ; and wet plants put into hot paper will 
require changing very soon, to prevent their turning black, for hot damp without ven- 
tilation produces fermentation, and spoils the specimens. 
237. For pressing plants, various more or less complicated and costly presses are 
made. None is better than a pair of boards the size of the paper, and a stone or other 
heavy weight upon them if at home, or a pair of strong leather straps round them if 
travelling. Each of these boards should be double, that is, made of two layers of thin 
boards, the opposite way of the grain, and joined together by a row of clenched brads 
round the edge, without glue. Such boards, in deal, rather less than half an inch 
thick (each layer about 2| lines) will be found light and durable. 
238. It is useful also to have extra boards or pasteboards the size of the paper, to 
separate thick plants from thin ones, wet ones from those nearly dry, etc. Open 
wooden frames with cross-bars, or frames of strong wire-work lattice, are still better 
than boards for this purpose, as accelerating the drying by promoting ventilation. 
239. The more frequently the plants are shifted into dry paper the better. Except- 
ing for very stiff or woody plants, the first pressure should be light, and the first shift- 
ing, if possible, after a few hours. Then, or at the second shifting, when the specimens 
will have lost their elasticity, will be the time for putting right any part of a specimen 
which may have taken a wrong fold or a bad direction. After this the pressure may 
be gradually increased, and the plants left from one to several days without shifting. 
The exact amount of pressure to be given will depend on the consistence of the speci- 
mens and the amount of paper. It must only be borne in mind that too much pres- 
sure crushes the delicate parts, too little allows them to shrivel, in both cases inter- 
fering with their future examination. 
240. The most convenient specimens will be made, if the drying-paper is the same 
size as that of the herbarium in which they are to be kept. That of writing-demy, 
rather more than 16 inches by 10j inches, is a common and very convenient size. A 
small size reduces the specimens too much, a large size is both costly and inconvenient 
for use. 
241. When the specimens are quite dry and stiff, they may be packed up in bundles 
with a single sheet of paper between each layer, and this paper need not be bibulous. 
The specimens may be placed very closely on the sheets, but not in more than one 
layer on each sheet, and care must be taken to protect the bundles by sufficient cover- 
ing from the effects of external moisture or the attacks of insects. 
242. In laying the specimens into the herbarium, no more than one species should 
ever be fastened on one sheet of paper, although several specimens of the same species 
may be laid side by side. And throughout the process of drying, packing, and laying 
in, great care must be taken that the labels be not separated from the specimens they 
belong to. 
243. To examine or dissect flowers or fruits in dried specimens it is necessary to 
soften them. If the parts are very delicate, this is best done by gradually moistening 
them in cold water ; in most cases, steeping them in boiling water or in steam is much 
quicker. Very hard fruits and seeds will require boiling to be able to dissect them 
easily. 
244. For dissecting and examining flowers in the field, all that is necessary is a pen- 
knife and a pocket-lens of two or three glasses from 1 to 2 inches focus. At home it 
is more convenient to have a mounted lens or simple microscope, with a stage holding 
a glass plate, upon which the flowers may be laid ; and a pair of dissectors, one of 
which should be narrow and pointed, or a mere point, like a thick needle, in a handle; 
the other should have a pointed blade, with a sharp edge, to make clean sections across 
the ovary. A compound microscope is rarely necessary, except in cryptogamic botany 
and vegetable anatomy. For the simple microscope, lenses of |, 1, and 1^ inches 
focus are sufficient. 
245. To assist the student in determining or ascertaining the name of a plant be- 
longing to a Flora, analytical tables should be prefixed to the Orders, Genera, and 
e 
