But the yellow dead-nettle is the most interesting; it gives so useful a lesson in practical botany. The stem is perfectly square; the leaves grow two together; the large golden-coloured blossoms are set in verandahs round the stalk, each particular flower shaped like the jaws of some terrible wild beast, wide-open and ready to bite, while the stamens are invariably four in number--a pair of long ones and a pair of short ones. The seeds, also, are exactly four. Whenever these peculiarities co-exist in a plant, we may be sure that there is nothing deleterious about it. More than fifty different plants formed on this plan grow wild in England, and considerably over two thousand in foreign countries, and not one of them is in the least degree noxious, either to quadruped or to man. Many are aromatic, and used with food, as thyme, sage, mint, basil, and penny-royal; while others are useful for medicinal tea, as balm and ground-ivy. Rosemary, lavender, and bergamot belong to the same fragrant family. The great object of botanical science is to determine such facts as these, _i.e._, to make out the relation between the form of a plant and its properties;--can a science of such useful, practical aim be justly deemed, as by some, mere "learned trifling?" Surely not. No slight advantage has that man over his fellows who, when he is walking through the meadows, or when he emigrates to a distant land, can discriminate between the poisonous plant and the wholesome, simply by examining the leaves and flowers. We do not mean to say that every individual plant in the world has its exact quality unmistakably configured upon it. The concurrence is between certain general properties and certain great types or plans of organisation, taking note of which latter we gain a good general idea of the former. The _particular_ nature must be learned by special inquiry. Though the yellow dead-nettle, for example, is shown by its general structure to be devoid of anything bad, it cannot be told whether it is fit to eat until tasted and tried. To persons who have an idea of emigrating, or whose children are likely to go abroad, botany is of the very highest service, for in foreign countries men are thrown upon their own resources, and to be compelled by ignorance to look upon every leaf as a possible poison is helplessness of the most wretched kind.