or, if any object to this word, for what use are the various organs of the plant? To answer this question is the work of the botanist: he examines the root, the stem, the leaf, the flower, and the fruit. In this investigation he has been successful, so that most of the plant machinery is now understood in its relations to the individual plant and to the succession of plants. Who doubts the use of the root and leaf in taking up and elaborating nutriment for the plant? Who doubts the use of the anther in producing pollen, or of the pollen grains in fertilizing the seed? Although we may be uncertain about the use of some parts, it does not affect the certainty of our knowledge respecting those we have mentioned. Let us push our inquiries further, and see if we find in the structure of the plant any contrivances, or in its development any variations of form, not required by the economy of the plant itself. We omit for the present all discussion as to the method by which these were produced, or how they came to be, but simply inquire if there are such. Selecting a few from the many, we might inquire: For what purpose are the petals of the flower, the crown of beauty, to the plant? Certainly they are not absolutely essential in the production of seed, for many plants are without them. And if in any case they are deemed essential, certainly the beautiful pattern of the petal, its numberless modifications. and delicate tints, adjusted with masterly accuracy, are not necessary parts in the economy of plants. Of what use to the plant is that row of sterile flowers that adorns so many of our Compositae, the Rudbeckias and Helianths; or that curious circle of sterile flowers bordering the cymes of Hydrangeas and some of our Viburnums? We may be told that they have no use, or that these apparently useless parts will at some time be found to be of importance in the economy of the plant, aiding directly or indirectly in the perpetuation of the species, as the honey of plants attracts bees, and thus secures the continuance of the species by the fertilization of the seed. We will go one step further, then, and ask: What end is subserved by double flowers? All

agree that one use of the flower is to produce seed. But the perfectly double flower loses the organs of reproduction. The rose unfolds its stamens and pistils into petals, and thus gains in beauty, till it becomes the perfection of a flower, but all at the expense of seed. What use, in the economy of the plant, does the flower subserve when it can no longer produce seed? It does not perpetuate the species, and it is a draft upon the nutriment that would otherwise go to build up the plant that produces it. By becoming double, the flower has ceased to be of advantage either to the species or the individual plant. But does Nature thus defeat her own ends, and provide for the destruction of some species by the very law of their growth? Not at all. In every plant which by cultivation is so far changed as to lose the power of producing seed, there is some other provision for the propagation of the plant, as by slips, by grafting, by bulblets, and the like. Nature seems thus to provide, in the structure of other parts of these plants, for the development of their flowers in the line of beauty at the expense of seed.

Let us examine another group of plants, belonging to the same natural order as the rose. For what purpose is the fruit of the apple tree, the pear tree, and the peach? Their seed is evidently for the propagation of the species. But still we ask: For what purpose are the apple and the peach? The germ is in the seed, or within the stone. The economy of the plant does not require that the covering of the seeds should be increased in quantity or heightened in flavor, for they come to their fullest development in the unchanged native fruit. If the improvement of size and flavor is not for the seed, it has no relation to the plant. And probably no candid person will contend that the change in cultivated fruits which renders them more valuable to man, has any more relation to the wants of the individual plant, or of the species, than the milk of the mother has to her own wants. If this change has any purpose at all, it is for something outside of the plant. The seed is not for the plant that produces it, but for the species. The change of covering, as

already indicated, is of no advantage to the seed. Its increase in size is therefore a draft upon the tree, without having any relation to the species. So far as the economy of the plant is concerned, it is a mistake. The machinery is out of order. There is an absolute throwing away of material and of vital energy.

We are now prepared to introduce and illustrate certain propositions, which seem warranted by plant development:

1. In some plants the idea of beauty is the most prominent idea, inasmuch as under the best cultivation the variation of these plants is always in the line of beauty. The beauty of the flower the rose, for example often increases at the expense of the reproductive organs, until the power of producing seed is lost.

2. In other plants, utility of fruit is the prominent idea, as in the apple and the peach. Such plants, under careful cultivation, produce larger and more delicious kinds of fruit, without increase of beauty in the flower.

3. From these two propositions another follows: that the plants best known to us from long continued cultivation can be readily divided into two great series, without reference to their botanical relationship, but according to their lines of development. In one series utility of fruit is the prominent idea; and in the other, beauty of flower; as under the best cultivation these series are developed in these two directions respectively.

The idea of utility is not manifested by fruit alone. The sugar of the sugar-cane constitutes its utility, while that of the Indian corn lies in its grain. These plants, so nearly allied botanically, are developed in these two directions, according to the leading idea in their products. The apple and the rose, already referred to, belong to the same botanical family; yet they are developed, in nearly all their variations, in opposite directions. The potato has, for its leading idea the formation of underground stems or tubers; while its brother, the tomato, has for its idea the production of a fruit corresponding in structure to the potato-grape.

They show this in all their variations. In the pine tree the leading idea is wood, and in the mint, essential oil. But in such plants as do not readily produce varieties, the line of development is determined with difficulty.

4. Some plants in their native state give indications of the kind of change likely to take place in them by cultivation. The rose, for example, by its large corrolla in comparison with the fruit, shows that change of flower is most likely to take place. In the apple, the large fleshy fruit indicates a tendency to variation and improvement in that direction. The Viburnum Opulus, the Hydrangea, and other plants, by the circle of sterile flowers, much larger than the fertile flowers, indicate change in the direction of beauty. These beautiful circles of sterile flowers in some of our native shrubs, and the neutral rays of some of our Compositae, may be regarded as ornaments, rather than as of use in the economy of the plant. When, therefore, a new plant is brought under cultivation, there is little doubt in what direction it will vary, if at all. The increase of beauty in the flower by doubling, and the increase of the fruit in size, beauty, and flavor, are of no advantage to the plant itself, nor to the species; but in some cases they are a draft upon the plant for no purpose in its own economy.

5. Those plants that by variation lose the power of producing seed can always be propagated in other ways, as by slips or bulbs. Nature, as though careful for the preservation of the species, never allows any plant, by its own law of growth, to lose the power of producing seed, unless she has given to it means other than the seed for the perpetuation of its kind.

6. Variation is most common and rapid in those plants which are most useful to man for cultivation, and which must go with him over most of the earth. It may be said that they are most useful because they happen to vary. But their readiness to vary, certainly was not the cause of their first cultivation. They were selected for some particular good, as for fruit, or for beauty of flower, or some other VOL. XXI. No. 82.

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useful property. The characteristic for which each one was first selected, was the leading idea of the plant, and in that direction all its variations under cultivation have tended. The rose, in all its varieties, is to-day cultivated for the same reason for which it was first cultivated-for its beauty; the apple tree for its fruit, the sugar cane for its sweetness, and so on through the list of cultivated plants. We might multiply propositions and examples, if our space allowed. As they would not differ in kind, they are not needed for the argument. Apparent exceptions to the propositions already stated, may undoubtedly be pointed out, for it is well understood by naturalists that Nature does nothing per saltum. Hardly a group of plants can be examined in which there will not be found one or more that the family description will not embrace in all particulars. There are also some plants so valuable for several purposes, that it would be difficult to determine in every case the leading idea. They are made for a double purpose, and may develop in either direction. The apple tree with double blossoms, or the tomato with tubers upon it, would not therefore, with any candid person, affect the bearing of the propositions. If a law of nature is really discovered, all exceptions are either merely apparent, or if real, are found to be special provisions for some wise purpose. It is the general law of variation. that we now wish to present for consideration in the propositions just enunciated. If these propositions have any significance, to what do they tend? Certainly to show that the vegetable kingdom is not an end to itself. Men and animals do not make use of plants because they happen to be what they are; but the plants are constituted as they are for the sake of the animal kingdom, and many of them with a direct reference to man as an intellectual and moral being. It is by the law of variation that they are most perfectly fitted for these high purposes.

In almost every department of plant-life the changes can be referred primarily to the good of the plant itself, and thus it is easy to say, and no doubt easy for some to believe, that