2 52 
THE HAND-BOOK OF GARDENING. 
‘‘In all cases, the more light plants are exposed to, the hardier they 
will be, provided they he not gorged with too watery food; and the 
less light they have, the more feeble, sickly, and yellow they will be. 
Light from above, also is greatly better than side light.” 
“The importance of wide planting, in most cases, will, therefore, 
be obvious; for if potatoes, cabbages, or other plants are crowded to¬ 
gether, they become (at least at their sides) nearly as much shaded 
from the light by each other, as if growing under trees." 
Air.---“ The importance of a free circulation of air to the healthy 
growth of plants must be obvious; and hence a garden cooped up 
between high walls or bushes, even though it have plenty of sun¬ 
light, which is still more indispensable than free air, will never pro¬ 
duce good crops. It has been supposed by some also, that plants 
require to be somewhat moved and shaken by the winds, as a sort of 
exercise for circulating the sap and the pulp, insomuch as they can¬ 
not take walking exercise like animals. This, however, is only an 
ingenious fancy.” 
Growth of Plants. ---“ When plants are stripped of their 
leaves by accident, such as by the ravages of caterpillars, or the 
browsing of cattle, they either die or become sickly, till new leaves, 
as will happen in vigorous plants, sprout again to prepare the neces¬ 
sary supplies of pulp.” 
“It is, therefore, an error to pick off leaves, as is sometimes done 
with the intention of exposing fruit, such as grapes, to the sun to 
hasten their ripening; for a supply of pulp is still more important to 
their ripening than such exposure, and without leaves no pulp can 
be formed.” 
Rejection of Plants, Rotation of Crops.-— “The fact has 
been long known to gardeners and farmers, that they could not get 
good crops of the same kinds from the same piece of ground, season 
after season, though the cause of this has only been investigated of 
late years, and has been proved, by experiments of Brugmans and 
Macaire, not to arise, as was formerly alleged, from the food in the 
soil being exhausted, since all plants feed nearly alike, but from the 
excrementitious slime which acts upon the same sort of plant that 
produce it, as a poison. Thus the slime from a crop of cabbages will 
greatly injure another crop of cabbages, though it will do little or no 
harm to potatoes or peas; while the slime from peas will injure peas, 
though it might not injure cabbages or turnips.” 
“ When this is known, it will prevent two successive crops of the 
same kind from being tried, unless the ground be so trenched and 
dug as to bury the slime deeper than the roots can reach. In many 
