122 
THE CULTIVATOR. 
243. The seed is nourished by the same meiftis as the fruit; and, like 
it, will be more or less perfectly formed, according to tho abundance of 
its nutriment. 
244. The plant developed from the embryo in the seed, will be in all 
essential particulars like its parent species. 
245. Unless its nature has been changed by hybridising. (204.) 
246. But although it will certainly, under ordinary circumstances, re¬ 
produce its species, it will by no means uniformly reproduce the particu¬ 
lar variety by which it was borne. 
247. So that seeds are not the proper means of propagating varie¬ 
ties. 
243. Nevertheless, in annual or biennial plants, no means can be em¬ 
ployed for propagating a variety, except the seeds; and yet the variety is 
preserved. 
249. This is accomplished solely by the great care of the cultivator, and 
happens thus. 
250. Although a seed will not absolutely propagate the individual, yet 
as a seed will partake more of the nature of its actual parent than of any 
thing else, its progeny may be expected, as really happens, to resemble 
the variety from which it sprung, more than any other variety of its spe¬ 
cies. 
251. Provided its purity ha? not been contaminated by the intermix¬ 
ture of other varieties. 
252. By a careful eradication of all the varieties from the neighborhood 
of that from which seed is to be saved, by taking care that none but the 
most genuine forms of a variety are preserved, as seed-plants: and by 
compelling by transplantation a plant to expend all its accumulated sap in 
the nourishment of its seeds, instead of in the superabundant produc¬ 
tion of foliage, a crop of seed may be procured, the plants produced by 
which will, in a great measure, have the peculiar properties of the parent 
variety. 
253. By a series of progressive seed-savings upon the same plan, 
plants will be at length obtained, in which the habits of the individual 
have become as it were fixed, and capable of such exact reproduction 
by seed, as to form an exception to the general rule; as in turnips, radish¬ 
es, &c. 
254. But if the least neglect occurs in taking the necessary precau¬ 
tions (252 ) to ensure a uniform crop of seed, possessing the new fixed 
properties, the race becomes deteriorated, in proportion to the want of 
care that has occurred, and loses its characters of individuality. 
255. In all varieties those seeds may be expected to preserve their in¬ 
dividual characters most distinctly which have been the best nourished 
(243.); it is consequently those which should be selected in preference 
for raising new plants, from which seed is to be saved. 
256. When seed3 are first ripened, their embryo is a mass of cellular 
substance, containing starch, fixed carbon, or other solid matter in its ca¬ 
vities; and in this state it will remain until fitting circumstances occur to 
call it into active life. 
257. These fitting circumstances are, a temperature above 32° Fahr. 
a moist medium, darkness and exposure to air. 
253. It then absorbs the moisture of the medium in which it lies, in¬ 
hales oxygen (27S ), and undergoes certain chemical changes; its vital 
pow.-rs cause it to ascend by one extremity for the purpose of finding 
light, and of decomposing its carbonic acid (279.), by parting with its ac¬ 
cumulated oxygen, and to descend by the other extremity for the purpose 
of finding a constant supply of crude nutriment. 
259. Unless these conditions are maintained, seeds cannot germinate; 
and, consequently an exposure to light is fatal to their embryo, because 
(273.) oxygen will not be absorbed in sufficient quantity to stimulate the 
vital powers of the embryo into action, for the purpose of parting with it 
again, by the decomposition of the carbonic acid that has bden formed 
during its accumulation. 
X. sap. 
260. The fluid matter which is absorbed either from the earth or from 
the air is called sap. 
261. When it first enters a plant it consists of tvater holding certain 
principles, especially carbonic acid, in solution. 
262. These principles chiefly consist of animal or vegetable matter in a 
state of decomposition, and are energetic in proportion to their solubility, 
or tendency to form carbonic acid by combining with the oxygen of the 
air. 
263. Sap soon afterwards acquires the nature of mucilage or sugar, and 
subsequently becomes still further altered by the admixture of sfich solu¬ 
ble matter as it receives in passing in its route through the alburnum or 
newly formed woody tissue (65.) 
264. When it reaches the vicinity of the leaves it is attracted into them, 
and there, having been exposed to light and air, is converted into the se¬ 
cretions peculiar to the species. 
265. It finally, in its altered state, sinks down the bark, whence it is 
given off laterally by the medullary rays, and is distributed through the 
system. 
266. No solid matter whatever can be taken up by the roots; for this 
reason, metals, which in the state of oxydes are poisonous, arc perfectly! 
harmless in their metallic state, as mercury; and this is, no doubt, the 
cause vvhy liquid manure, which contain* all the soluble parts of manure 
in a fluid state, acts with so much more energy than stimulating substan¬ 
ces in a solid state. 
267. The cause of the motion of the sap is the attraction of the leaf- 
buds and leaves. 
268. The leaf-buds called into growth by the combined action of the 
increasing temperature and light of spring, decompose their carbonic 
acid (279.), and attract fluid from the tissue immediately below them; the 
space so caused is filled up by fluid again attracted from below, and thus 
a motion gradually takes place in the sap from one extremity to the 
other. 
269. Consequently the motion of the sap takes place first in the branch¬ 
es and last in the roots. 
270. For this reason a branch of a plant subjected to a high tempera¬ 
ture in w'inter, will grow while its stem is exposed to a very low tempe¬ 
rature. 
271. But growth under such circumstances will not be long maintained, 
unless the roots are secured from the reach of frost; for, if frozen they 
cannot act, and will, consequently, be unable to replace the sap of which 
the stem is emptied by the attraction of the buds converted into branches, 
and by the perspiration of the leaves. (XII.) 
272. Whatever tends to inspissate the sap, such as a dry and heated 
atmosphere, or an interruption of its rapid flow, or a great decomposition 
of carbonic acid by full exposure to light, hrs the property of causing ex¬ 
cessive vigor to be diminished, and flower buds to be produced. 
273. While, on the other hand, whatever tends to dilute the sap, such 
as a damp atmosphere, a free and uninterrupted circulation, or a great ac¬ 
cumulation of oxygeh in consequence of the imperfect decomposition of 
carbonic acid, has the property of causing excessively rapid growth, and 
an exclusive production of leaf-buds. 
274. Inspissated or accumulated sap is, therefore, a great cause of fer¬ 
tility. 
275. And thin fluid, not being elaborated, is a great cause of steri¬ 
lity. 
276. The conversion of sap into different kinds of secretion is effected 
by the combined action of Mr (XI.), Light (XI.), and Temperature. 
XI. AIR AND LIGHT. 
277. When an embryo plant (242.) is formed within its integuments, it 
is usually colorless, or nearly so; but, as soon as it begins to grow, that 
part which approaches the light, (the stem) becomes colored, while the 
opposite extremity (the root) remains colorless. 
273. The parts exposed to the air absorb oxygen at night, absorb car¬ 
bonic acid and part with oxygen again in day-light; and thus in the day¬ 
time puiily the air, and render it fit for the respiration of man. 
279. The intensity of this latter phenomenon is in proportion to the in¬ 
tensity of solar light to which leaves are directly exposed. 
280. Its cause is the decomposition of carbonic acid, the extrication of 
oxygen, and the acquisition by the plant of carbon in a solid state: from 
which, modified by the peculiar vital actions of species, color and secre¬ 
tions are supposed to result. 
281. For it is found that the intensity of color and the quantity of se¬ 
cretions are in proportion to the exposure to light and air, as is shown by 
the deeper color of the upper side of leaves, &c. 
232. And by the fact that if plants be grown in air from which light is 
excluded, neither color nor secretions are formed, as is exemplified in 
blanched vegetables; which, if even naturally poisonous, may, from want 
of exposure to light, become wholesome, as celery. 
283. When any color appears in parts developed in the dark, it is gene¬ 
rally caused by the absorption of such coloring matter as pre-existed in 
the root or other body from which the blanched shoot proceeds, as in some 
kinds of rhubarb when forced. 
284. Or by the deposition of coloring matter formed by parjs developed 
in light, as in the subterranean roots of beets, carrots, &c. 
2S5. What is true of color is also true of flavor, which equally depends 
upon light for its existence; because flavor is produced by chemical alte¬ 
rations in the sap caused by exposure to light. (229.) 
286. The same thing occurs in regard to nutritive matter, which in like 
manner is formed hy the exposure of leaves to light. Thus the potato 
when forced in dark houses contains no more amylaceous matter than pre¬ 
viously existed in the original tuber; but acquires it in abundance when 
placed in the light, and deposites it in proportion as it is influenced by light 
and air. Thus, also, if peaches are grown in wooden houses, at a dis- 
tance-fiom the light, they will form so little nutritive matter as to be una¬ 
ble to support a crop of fruit, the greater part of which will fall off. And 
for a similar reason, it is only the outside shoots of standard fruit trees 
that bear fruit. Considerations of this kind form in part the basis of prun¬ 
ing and training. 
287. Light is the most powerful stimulus that can be employed to excite 
the vital actions of plants, and its energy is in proportion to its intensity; 
so that the direct rays of the sun will produce much more powerful effects 
than the diffused light of day. 
