VoL. ill. 
AUGUSTA, GA., SEPTEMB’-R, I8|5. 
No. 
MOJSTICCJI^XUKASL, ©UTL5KE. 
AN OUTLINE OF TII^ FIRST PRINCIPLES OF 
IIOR rU^UL LURE : By John Lindl'ey, F R.S., &c., 
&c., Professor of Botany in the University of Lon- 
don, Slid Assistant Secretary of the Horticultural 
Society.— [CONCLUDED.] 
XII. PERSPIRATION. 
299. It is not, however, exclusively by the ac- 
tion of liHht and air that the nature of sap is al- 
tered. Evaporation is constantly going on du- 
ring the growth t f a plant, and sometimes is so 
copious, that an individual will perspire its own 
weight of water in the course of24 hours. 
300. The loss thus occasioned i^y the leaves 
is supplied by crude liuid, absorbed by the roots, 
and con veyed up the stem with great rapidity. 
301. The consequence of such copious per- 
spiration is the separation and solidification of 
the carbonized matter that is produced for the 
peculiar secretions of a species. 
302. For the maintenance of a plant in health, 
it ii indispensable that the supply ol fluid by Ihe 
roots should be continual and uninterrupted. 
303. II any thing causes perspiration to take 
place laster than it can be counteracted by the 
absorption of fluid from the earth, plants will 
be dried up and perish. 
304. Such causes are, destruction of spon- 
gioles, an- insufficient quantity of fluid in the 
soil, an exposure of the spongioles to occasion- 
al drvness, and a dry atmosphere. 
305. The most ready means _ol counteracting 
the evil consequences of an imperfect action ol 
the roots is by preventing or diminishing evapo- 
ration. 
306. Thi- is to be effected by rendering the 
atmosphere extremely humid. 
307. Thus, in curvilinear iron hnt-houses, in 
which the atmosphere becomes so dry in conse- 
quence of the heat, that plants perish, it is ne- 
cessary that the air should be rendered extreme- 
ly humid, by throwing water upon the pave- 
ment, or by introducing steam. 
308. And in transplantation in dry weather, 
evergreens, or plants in leaf, often die, because 
the spongioles are destroyed, or so far injured 
in the operation as to be unable to act, while the 
leaves never cease to perspire. 
309. The greater certainty of transplanting 
plants that have been growing in pots is from 
ih's latter circumstance intelligible ; 
310. While the utility of putting cuttings or 
newly transplanted seedlings into a shady, damp 
atmosphere, is explained by the necessity of 
hindering evaporation. 
XIII. CUTTINGS. 
311. When a separaie portion ol a plant is 
caused to produce new roots and branches, and 
to increase an individual, it is a cutting. 
312. Cuttings are of two sorts — cutli.ngs pro- 
perly so called, and eyes. (319.) 
313. A cutting consists of an internodium, 
or a part of one, with its nodus and leaf-bud. 
314. When the internodium is plunged in the 
earth it attrticts fluid from the soil, and nourish-^ 
es the bud until it can feed itself. 
315. The bud, feeding at first upon the matter 
in the internodium, gradually elongates up- 
w'ardsinto a branch, and sends organized matter 
downwards, which Irecomes roots. 
3lG. As soon as ft has established a commu- 
nication w'ith the soil, it becomes a new indi- 
vidual, exactly like that from which it was ta- 
ken. 
317. As it is the action of the leaf-buds that 
causes growth in a cutting, it follows that no 
cutting without a leaf-bud will grow; 
318. Unless the cutting has great vitality and 
power of forming advenlitious leaf-buds (119,) 
which sometimes happens. 
319. An eye is a leaf-bud without an interno- 
dium 
320. It only differs from a cutting in having 
no reservoir of food on which to exist, anil in 
emitting its roots immediately from tlie base' oi 
the leaf-bud into the soil. 
321. As cuttings will very often, if not al- 
ways, develope leaves before any powerful con- 
nection is formed between them and the soil, 
they are peculiarly liable to suffer from perspi- 
ration. 
332. Hence the importance of maintaining 
their atmosphere in an uniform state of humid- 
ity, as is effected by putting bell or other glasses 
over them. 
323. in this case, however, it is necessary that 
if air-tight covers are employed, such as bell 
glasses, they should be from time to time vre- 
moved and replaced, for the sake of getting rid 
ol excessive humidity. 
334. Lavers differ from cuttings in nothing 
except that they strike root into the soil while 
yet adhering to the parent plant. 
335. Whatever is true of cuttings is true of 
layers, except that the latter are not liable to 
suffer by evaporation, because of their commu- 
nication with the parent plant. 
336. As cuttings strike roots into the earth by 
the action of leaves or leaf-buds, it might be 
supposed that they will strike most readily 
when the leaves or leaf-buds are in their great- 
est vigor. 
337. Nevertheless, tnis power is controlled so 
much by the peculiar vital powers of different 
species, and by secondary considerations, that it 
is impossible to say that this is an absolute 
rule 
338. Thus 'Dahlias and other herbaceous 
plants will strike roots freely when cuttings are 
^^e.^v young; and Heaths, Azaleas, and other 
hard wooded plants, only when the wood has 
just begun to harden. 
339. The former is, probably, owing to some 
specific vital excitability, the force of which we 
cannot appreciate ; the latter either to a kind of 
torpor, which seems to .seize such plants when 
their tissue is once emptied of fluid, or to a na- 
tural slowness to send downwards woody mat- 
ter, whether for wood or not, which is the real 
cause of their wood being harder. 
330. It ripened cuttings are upon the whole 
the most fitted lot multiplication, it is because 
their tissue is less absor'bent than when yi.mnger, 
and that they are less likely to suffer either from 
repletion or evaporation. 
331. For, to gorge tissue with food, before 
leaves are in action to decompose and assimilate 
it, is as prejudicial as to emp'y tissue by the ac- 
tion of leaves, before spongioles are prepared 
to replenish it. 
332. For this reason pure silex, in which no 
stimuliiting substances are contained (silver 
sand,) is the best adapted for promoting the root- 
ing of cuttings that strike with difficulty. 
333. And for the same reason, cuttings with 
what gardeners call a heel to them, or apiece 
of the older wood, strike root more readily than 
such as are not so protected. The greater age 
of the tissue of the heel renders it less absorb- 
ent than tissue that is altogether newly Ibrmed 
334. It is to avoid the bad effect of evapora- 
tion that leaves are usually for the most part 
removedfrom a cutting, when it is first prepared. 
XH/. SCIONS. 
335. A scion is a cutting (311,) which is 
caused to grow upon another plant, and not in 
earth. 
336. Scions are of two sorts, scions properly 
so called, and buds (354.) 
337. "Whatever is true of cuttings is true 
also of scions, all circumstances being equal. 
338. When a scion is adapted to another 
plant, it attracts fluid from it lor the nourish- 
ment of its leaf-bnds until they can feed ihem- 
seives. 
339. Its buds thus fed gradually grow upwards 
into branches, and send woody matter down- 
wards, which IS analogous to roots. 
340. At the same time the cellular substance 
of the scion and its slock adheies (19,) so as to 
form a complete organic union. 
341. The woody matter descending from the 
bud passes through the cellular substance into 
the slock, where it occupies the same situation 
as would have been occupied by woody matter 
supplied by buds belonging to the stock itself. 
342. Once un ited, the scion covers the wood 
of the stock with new wood, and causes the pro- 
duction of new roots. 
343. But the character of the woody matter 
sent down by the scion over the wood of the 
Slock being rietermined by the cellular substance, 
which has exclusively a horizontal clevelope- 
ment, (73,) it follows that the wood ol the stock 
will always remain apparently the same, al- 
though it is furnished by the scion. 
344. Some scions will grow upon a stock 
wdthout being able lo transmit any woody mat- 
ter into it; as some Cacti. 
345. When this happens, the adhesion of the 
tw'o takes place by the cellular substance only, 
and the union is so imperfect that a slight degree 
of violence suffices to dissever them. 
346. And in such cases the buds are fed by 
their woody matter, which absorbs the ascend- 
ing sap from the stock at the point where the ad- 
hesion has occurred; and the latter, never aug- 
menting in diameter, is finally overgrown by 
the scion. 
347. W^hen, in such instances, the communi- 
cation between the stock and the scion is so 
much interrupted that the sap can no longer as- 
cend with sufficient rapidity into the branche.s, 
the latter die; as in many peaches. 
348. This incomplete union between the 
scion and its stock is owing to some constitu- 
tional or organic difference in the two. 
349. Therefore care should be taken that when 
plants are grafted on one another, their .con- 
stitution should be as nearly aspossible identical. 
350. As adhesion of only an impertect nature 
takes place when the scion and stock are, to a 
certain degree, dissimilar in constitution, so will 
no adhesion whatever occur wffien their consti- 
tutional differences are very decided. 
351. Hence it is only species very nearly al- 
lied in nature that can be grafted on each other. 
352. As only similar tissues will unite (19,) 
it is necessary in applying a scion to the stock, 
that similar parts should be carelully adapted lo 
each other; as bark to bark, cambium to cam- 
bium, and alburnum to alburnum. 
353. The second is more especially requisite, 
