290 



CULINARY OR KITCHEN GARDEN. 



other vegetable matter subjected to the same 

 amount of fermentation, either prosper so well, 

 or recover from a sickly state so soon as they 

 do in pits heated by stable manure, all other 

 conditions being the same. Practically we 

 know this, and account for the difference in the 

 almost total absence of ammoniacal gases, or 

 other fertilising matter, in the former when 

 compared with the latter. So apparent is this-, 

 that some of our best cultivators — Mr Fleming 

 of Trentham, for example — have recommended 

 pigeons' dung, or other highly - enriched ma- 

 nures, to be mixed with the water in the tanks, 

 to bring about this invigorating state in the 

 atmosphere of pine-stoves, which are deficient 

 in it — although heat and moisture are abun- 

 dantly supplied by the tanks. Sickly plants, in 

 pots, plunged in a common dung-bed, rapidly 

 recover ; and pines grown in such material, 

 although their roots are also confined within 

 pots, attain a larger size and greater vigour. 

 Melons grown in pots suspended by their 

 rims, and placed over a vault heated by dung 

 linings, are found to prosper as well as when 

 planted in soil laid immediately over the hot- 

 bed. These and many other instances could be 

 given of the healthy condition of plants, when 

 grown in an atmosphere highly charged with 

 gases arising from dung in a state of fermenta- 

 tion, and while their roots are almost precluded 

 from being affected by them. That the plants 

 so circumstanced must derive no ordinary share 

 of their nourishment in a gaseous form is pretty 

 evident, and it is equally so that that nourish- 

 ment is not conveyed to them by their roots. 

 It follows, therefore, that the leaves are the 

 organs through which it is supplied. If, there- 

 fore, such an operation goes on in pits and hot- 

 houses, it necessarily follows that the same 

 action is going on in the open air — with this 

 difference only, that, in the former case, the 

 atmosphere is more limited and the supply 

 more abundant than in the latter. These effects 

 have been discovered and accounted for by men 

 of observation and intelligence — such as those 

 who practise in the highest grades of artificial 

 cultivation ; while the more superficial go-by-rote 

 practitioners scarcely bestow a thought upon 

 the matter. 



Absorption by the root is the process by which 

 plants take up their food from the soil, or from 

 those ingredients which are artificially added to it, 

 called manures. The investigations of Hedwig 

 and Decandolle have long ago set this matter at 

 rest, at least to the satisfaction of vegetable phy- 

 siologists. For the satisfaction of others, we 

 may state that the food of all vegetables must 

 be reduced, by some means or other, to an 

 aqueous form, and in that state it is absorbed 

 by the spongioles, or sponge-like appendages 

 situated at the points of the fine fibres or root- 

 terminators, and from them conveyed through 

 the roots to the stem, branches, and leaves of 

 the plant. 



Absorption by the leaves was first elucidated 

 by Duhamel and Marriotte, and by the experi- 

 ments made soon afterwards by M. Bonnet of 

 Geneva, chiefly with a view to ascertain whether 

 the absorbing power was alike on both surfaces 



of the leaf. The deductions drawn by him were, 

 that the leaves of herbs absorb moisture chiefly 

 by the upper surface, and the leaves of trees 

 by the under surface. The cause of this dis- 

 parity between the absorbing surfaces of the 

 leaves of trees and herbs was not very clearly 

 shown by Bonnet. Keith conjectures that the 

 physical cause might be the existence of a greater 

 or smaller number of pores in the leaves of 

 the herb and tree respectively. The chemical 

 cause would be the peculiar degree of affinity 

 existing between the absorbing organs and the 

 fluid absorbed. Duhamel, looking to the phy- 

 sical cause merely, regarded the lower surface 

 of the leaf of the tree as being endowed with the 

 greater capacity of absorbing moisture, chiefly 

 for the purpose of catching the ascending exhala- 

 tions which must necessarily come in contact 

 with it as they rise, but which might possibly 

 have escaped it if absorbable only by the upper 

 surface, owing to the increased rapidity of their 

 ascent at an increased elevation ; and regarded 

 the upper surface of the leaf of the herb as being 

 endowed with the greater absorbing power, 

 owing to its low stature, and to the slow ascent 

 of exhalations near the earth. "This," says 

 Keith, " does not throw much light upon the 

 subject ; and the experiments were still deemed 

 insufficient, as not representing to us the actual 

 phenomena of vegetation, though the fact of the 

 absorption of moisture by the surface of the 

 leaf is fully confirmed by such phenomena." 

 The leaves absorb both moisture and gaseous 

 food by means of the stomata, or, in the absence 

 of pores or stomata, by means of the absorbent 

 power of the epidermis, not only of the root and 

 leaf, but often, as it may be believed, by the 

 other parts of the plant also — at least when they 

 are soft and fleshy, as must be the case in suc- 

 culent plants, which are for the most part de- 

 void of leaves altogether. 



§ 2, — ORGANIC MANURES. 



Stable-yard manure. — The most important, 

 and hence the most general in use of these, is 

 stable-yard manure, composed of vegetable mat- 

 ter, such as straw, bay, and other material em- 

 ployed either as food or litter to such animals 

 as the ox, the horse, the cow, the hog, &c. It 

 is valued in proportion to the quantity of their 

 excrements mixed with it, the amount of urine 

 with which it is saturated, and the manner in 

 which it is kept previous to its application to the 

 soil. The quality of the food, and the peculiar 

 construction of the digestive organs of the ani- 

 mal, affect it also in some degree ; and hence the 

 dung of one animal is of higher value than that 

 of others. " For," as Donaldson (On Soils and 

 Manures) remarks, "the same kind of food 

 given to animals of a different genus will yield 

 an excrement of a very different quality ; and 

 even when given to those of the same species, 

 and under the same treatment, a great differ- 

 ence will often be found, which can only be 

 attributed to the construction and action of the 

 constitutional organs. The dung of swine is of 

 a cold nature, inclining to form a saponaceous 



