rapidly, and the plant withers. Light exerts also a very great influence; the stronger the light the greater is the amount of water exhaled, and, generally speaking, the maximum occurs shortly after midday. During hot and dry weather a grass plant has been known to exhale its own weight in water during the twenty-four hours. From what has been now said, it will be seen how necessary are plants to animals, and animals to plants, as without the one the other would not long survive; for when the atmosphere became exhausted of carbonic acid, which is formed by animals, the plants would have no means of building up starch, etc. The great difference between plants and animals should also be noted, that whereas the plant is continually feeding only to increase and store up material, the animal feeds to increase and repair the waste that is continually proceeding. LIFE-FORMS OF PLANTS --EDWARD CLODD If the life-forms of the past somewhat baffle us by their scantiness and imperfectness, those of the present embarrass us by their abundance. But although the existing species of plants and animals are numbered by hundreds of thousands, and the tale is not yet complete, they are classified into a few primary divisions or sub-kingdoms, representing certain allied types, of which the several species included in each sub-kingdom are modified forms. For example, flies and lobsters, beetles and crabs, are grouped in the sub-kingdom of the _Annulosa_, because they are alike composed of distinct segments; boys and frogs, pigs and herrings, are grouped in the sub-kingdom of the _Vertebrata_, because they alike possess an internal bony skeleton, the most important feature of which is the spine or vertebral column. And this classification is applicable alike to past and present organism, there being throughout the whole series of fossil remains no form, however unlike any existing living thing, that is not to be placed in one or other of the sub-kingdoms. Moreover, a fundamental unity underlies and pervades the whole, a unity of material, of form, and of function, the differences between organisms, from the slime of a stagnant ditch to the most complex animal, being in degree and in kind. Therefore, although each genus, nay, in most cases, each species, needs for its complete study the labor of a lifetime, it suffices for the majority of us, grateful for the results which the zeal of specialists has achieved, to acquaint ourselves with the essential characteristics which mark the main division of the twin sciences of _Botany_ and _Zoology_. Not only is this the only possible thing for us; it is the one thing needful for all, specialists and non-specialists, otherwise the significance of facts, in their relation and dependence, is missed; the larger generalizations are swamped in a sea of detail; we can not, as the phrase goes, see the wood for the trees.