Book I. PRINCIPLES OF VEGETABLE CULTURE. 279 



the bulbs are to be increased, and the contrary ; the water-shoots and leaf-buds of fruit- 

 trees ; the flower-stems of tobacco ; the male flowers and barren runners of the cucumis 

 tribe, &c. Hence the important operations of pruning, ringing, cutting off large 

 roots, and other practices for improving fruits and throwing trees into a bearing state. 

 At first sight these practices do not appear to be copied from nature ; but, indepen- 

 dently of accidents by fire, already mentioned, which both prune and manure, and of 

 fruit-bearing trees, say thorns or oaks, partially blown out by the roots, or washed out 

 of the soil by torrents, which always bear better afterwards, why may not the necessity 

 that man was under, in a primitive state of society, of cutting or breaking off branches 

 of trees, to form huts, fences, or fires, and the consequent vigorous shoots produced 

 from the parts where the amputation took place, or the larger fruit on that part of the 

 tree which remained, have given the first idea of pruning, cutting off roots, &c. It 

 may be said that this is not nature but art ; but man, though an improving animal, is 

 still in a state of nature, and all his practices, in every stage of civilisation, are as 

 natural to him as those of the other animals are to them. Cottages and palaces are as 

 much natural objects as the nests of birds, or the burrows of quadrupeds ; and all the 

 laws and institutions by which social man is guided in his morals and politics, are no 

 more artificial than the instinct which congregates sheep and cattle in flocks and herds, 

 and guides them in their choice of pasturage and shelter. 



1795. To form new varieties of vegetables, as well as of flowers and useful plants of 

 every description, it is necessary to take advantage of their sexual differences, and to 

 operate in a manner analogous to crossing the breed in animals. Hence the origin of 

 new sorts of fruits, grains, legumes, and roots. Even this practice is but an imitation 

 of what takes place in nature by the agency of bees and other insects, and the wind ; 

 all the difference is, that man operates with a particular end in view, and selects 

 individuals possessing the particular properties which he wishes to perpetuate or improve. 

 New varieties, or rather subvarieties, are formed by altering the habits of plants ; by 

 dwarfing through want of nourishment : variegating by arenacious soils; giving or 

 rather continuing peculiar habits when formed by nature, as in propagating from 

 monstrosities fasciculi of shoots, weeping shoots, shoots with peculiar leaves, 

 flowers, fruit, &c. 



1796. To propagate and preserve from degeneracy approved varieties of vegetables, it 

 is in general necessary to have recourse to the different modes of propagating by exten- 

 sion. Thus choice" apples and tree fruits could not be perpetuated by sowing their 

 seeds, which experience has shewn would produce progeny more or less different from 

 the parent, but they are preserved and multiplied by grafting ; others, as the pine-apple, 

 by cuttings or suckers ; choice carnations by layers, potatoes by cuttings of the tubers, 

 &c. But approved varieties of annuals are in general multiplied and preserved by se- 

 lecting seeds irom the finest specimens and paying particular attention to supply suitable 

 culture. Approved varieties of corns and legumes, no less than of other annual plants, 

 such as garden flowers, can only be with certainty preserved by propagating by cuttings 

 or layers, which is an absolute prolongation of the individual ; but as this would be too 

 tedious and laborious for the general purposes both of agriculture and gardening, all 

 that can be done is to select seeds from the best specimens. This part of culture is the 

 farthest removed from nature ; yet there are notwithstanding examples of the fortuitous 

 graft ; of accidental layers ; and of natural cuttings, as when leaves, or detached por- 

 tions of plants (as of the cardamine hirsuta) drop and take root. 



1797. The preservation of vegetables for future use is effected by destroying or render- 

 ing dormant the principle of life, and by warding off, as far as practicable, the progress 

 of chemical decomposition. When vegetables or fruits are gathered for use or pre- 

 servation, the air of the atmosphere which surrounds them is continually depriving them 

 of carbon, and forming the carbonic acid gas. The water they contain, by its softening 

 qualities, weakens the aflfinity of their elements ; and heat produces the same effect by 

 dilating their parts, and promoting the decomposing effect both of air and water. 

 Hence, drying in the sun or in ovens, is one of the most obvious modes of preserving 

 vegetables for use, as food, or for other purposes ; but not for growth, if the drying 

 processes is carried so far as to destroy the principle of life in seeds, roots, or sections of 

 the shoots of ligneous plants. Potatoes, turnips, and other esculent roots, may be pre- 

 served from autumn till the following summer, by drying them in the sun, and bury- 

 ing them in perfectly dry soil, which shall be at the same time at a temperature but a 

 few degrees above the freezing point. Corn may be preserved for many years by first 

 drying it thoroughly in the sun, and then burying it in dry cool pits, and closing these 

 so as effectually to exclude the atmospheric air. In a short time the air within is 

 changed to carbonic acid gas, in which no animal will live, and in which, without an 

 addition of oxygen or atmospheric air, no plant or seed will vegetate. The corn is thus 

 preserved from decomposition, from insects, vermin, and from vegetation in a far more 

 eflectual manner than it can be in a granary. In this way the Romans preserved tJieir corn 



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