WORMS, SNAILS, SLUGS, &C-, CONSIDERED. 93 



is subject in this climate, as Mr. Daniell has observed, is the uncertainty of 

 clear weather ; hut artificial warmth can be supplied or withheld at pleasure. 

 " After trying everything that I had seen recommended for the shrivelling of 

 grapes," says an experienced scientific gardener, " and feeling fully convinced 

 in my own mind, that want of light was one of the causes of this evil, I 

 thought I would try what effect proportioning the heat to the light would 

 do. This I did, and after several years' practice, I can assert that the 

 success has been beyond my expectation." (Gard. Mag.^ vol. vi., second 

 series, p. 529.) 



287. The absence of light, as we have before mentioned (278), is necessary 

 to render certain bitter or unwholesome parts of plants fit for culinary pur- 

 poses ; and the diminution of light is frequently had recourse to, when the 

 habitation of plants which grow in shady places is to be imitated, and when 

 the perspiration from the leaves of plants is to be diminished. In all cases 

 of rooting plants from cuttings which have the leaves on, the diminution of 

 perspiration, by shading them from the direct rays of the sun, is necessary, 

 till the cuttings have taken root ; and this is also more or less the case with 

 all rooted plants which are transplanted with the leaves on, for some days 

 after transplanting. When plants are in a dormant state, and without leaves, 

 no light is requisite to maintain them in a healthy state ; and even such 

 evergreens as are in a state of comparative rest require very little. Hence 

 Orange-trees and other greenhouse evergreens, may be kept through the 

 winter in an opaque-roofed conservatory ; and deciduous plants, which have 

 lost their leaves, may be kept through winter in houses or in cellars into 

 which no light is admitted. Plants which naturally grow in the shade (122), 

 are not here taken into consideration. 



CHAPTER V. 



WORMS, SNAILS, SLUGS, REPTILES, BIRDS, &c., CONSIDERED WITH 

 REFERENCE TO HORTICULTURE. 



288. THE natural uses of plants are for the support of animals, and hence 

 every plant, whether in a wild state or in cultivation, is more or less liable 

 to their attacks. The most universal enemies to plants in British gardens 

 are insects, snails, slugs, and earth-worms ; but they are also subject to be 

 devoured or injured by reptiles, birds, and some quadrupeds. With the 

 introduction of new species and varieties of plants, the refinements of garden 

 cultivation in forcing-houses, and the cultivation of tropical plants in stoves, 

 the attacks of ordinary insects have been more severely felt, and several new 

 species have been introduced. Hence, to prevent the increase of insects and 

 other garden vermin, or to destroy them after they have commenced their 

 attacks, has become an important element in garden-culture. 



289. Till about the end of the last century very little attention was paid 

 to garden vermin by horticultural writers. Birds were considered to be the 

 chief enemies of gardeners, and they were directed to be scared away or shot 

 at on account of the injury they did to the rising seeds, or the ripe fruit 

 which they ate or destroyed. The injuries done by insects of whatever kind 



