214 The seven VEGETABLE F A xM I L I E S. 
Plants, thofe which grow at the bottom of their deep waters, are as fimple 
and as poor as our own. It is for the fame Reafon feveral Plants of the 
lighter Regions, tho’ they grow' freely, will not flower in our Stoves: and 
hence more Light will make fome flower in Europe, which clfe do it 
rarely and poorly. The Brunfwigian Amaryllis is one inftance j and fome 
cf the more backward Aloes give another. 
Where Vegetable Nature receives the greateft Perfedlion in Form and 
Colour, there alfo the Virtues of Plants are found the moft exalted. The 
Spices, and the fragrant Gums, come from the fame bright Regions with 
the gayefl; Flowers ; and from the imperfetH: trials we can make here, 
Light has its ihare with Heat in their Produdtion. 
These arc the mofl; elTential efFcds of Light : but the moft obvious 
is the cxpanfloii of the Leaves of Trees and Herbs j this is their ftate of 
Waking ; oppofed to that which has been called the Sleep of Plants. This 
clofing of their Leaves 1 have been fo happy to fhew, by a multitude of 
experiments, is the cfleft only of the abfence of Light; and that their 
Expanflon, vvliich is called their Waking, is the immediate effedt of the 
prefence of that great Agent ; and is proportioned always to its degree or 
quantity. 
The Plant which I have found anfwer the moft readily of all to thefe 
Experiments, and which is therefore the beft and fitteft for them, is a 
voung Abrus. Such a one I have reprefented in the annexed Plate, fee 
Plate XXL in its two ftates of perfedl Sleep and perfedl Waking; the 
ftates of full Expanflon and entire Clofure. The Waking Plant is juft 
what it appears in moderate Day-light : the Sleeping one is a reprefentation 
of the fame Plant in the Night. 
It cannot be needful I fliould repeat here what I have publifhed in a 
preceeding Trcatife on the Sleep of Plants ; but it may be fit to fay in 
general, that fuch a ftate as that reprefented in the Sleeping Plant, and 
which comes on naturally at Night, may be brought on at pleafure at 
Noon-Day, by fliutting up the Flerb in Darknefs ; and that the effed; of 
Light in the Expanflon of its Leaves is fo regular, that they may be made 
to rife and fink in fmall Gradations, by removing the Pot wherein it grows, 
to different parts of the fame room, nearer to, or farther from, the Win- 
dows. 
The farther Effeds of Light on Vegetables, and the refult of them, 
affords a fubjed worthy the beft attention of all who love thefe ftudies : 
and, perhaps, a knowledge of this is all we want to perfed the Fhilofophy 
of Plants. 
INDEX. 
