its truth by facts clearly seen by himself, and had afterwards pursued the subject of dew through its various ramifications by means of the clue which would have been thus obtained, he must soon have acquired a knowledge of the theory which has lately been submitted by myself to the consideration of the learned, and which he, as a member of that body, has pronounced to be just. But I must, on the other hand, be permitted to say, that, if Dr Young, forgetting that Newton became a glass-grinder in the service of science, will neglect to employ, for the increase of natural knowledge, the slow and laborious method of observation and experiment, and will frequently exhibit his speculations in a manner unsuited to the capacities of ordinary men, he ought not to think it strange that opinions advanced by him on difficult points of philosophy are not, agreeably to his own remark at the end of the criticism, received as truths beyond doubt, and are often not understood."

This is smartly said, but cannot, we think, be admitted as a sufficient answer to Dr Young's strictures.

It will naturally be asked, What then remains for Wells? If all the phenomena had been observed, and even the theory pointed out, before he began his experiments, is there any merit at all to which he can justly lay claim? We answer, that to Wells belongs the rare merit of seeing clearly where other men saw obscurely; of grasping the whole, while other men only held detached parts; of bringing the scattered and somewhat incoherent labours of other inquirers to bear upon his own experiments, which were undertaken with clearer views, and consequently a more direct purpose, than those of his predecessors; and the final result of his long and patient inquiry was the establishment of a theory of extreme beauty and simplicity, the truth of which subsequent inquiry has only tended to confirm: not that Dr Wells is to be ranked as the author of this theory, but that his Essay was, as Dr Whewell remarks,* "one of the books which drew most attention to the true doctrine, in this country at least."

Still, however, it is but an act of justice to rescue from oblivion the claims of such men as Le Roy, Pictet, Patrick * History of the Inductive Sciences. 3d edit. vol. ii. 1857.

Wilson, Prévost, and others. Honour to them does not diminish the merit due to Wells. It only restores to its proper course the progress of discovery, where in this, as in other branches of science, and indeed in other relations in life, men are as mutually dependent on each other for intellectual progress as they are for the supply of their ever-recurring daily wants. It is not given to one man to begin, continue, and complete the journey into the undiscovered land unaided and alone; others have preceded him in the attempt, and have left the impressions of their footsteps on the virgin soil, which, however faint and uncertain, serve nevertheless as guides to subsequent explorers.

The Theory of Terminal Fructification in the Simple Plant, of Ovules and Pollen, and of Spores. By Dr MACVICAR, Moffat.*

It is generally admitted, and indeed is obvious to every observer, that symmetry prevails to a great extent in the forms at once of the mineral, the vegetable, and the animal kingdom. Nay, it manifests itself most beautifully in the forms and orbits of the heavenly bodies, and in the phenomena of light and colours; and in a word, symmetry, makes its apparition, more or less, everywhere. But to this, it must be confessed, that there sometimes seem at least to be remarkable exceptions, and that, too, where one would naturally expect symmetry most to prevail. Of these one of the most striking is this, that in a simple plant, a plant with a single axis, the fructification is always terminal, so that, morphologically viewed, the fully developed plant presents its axis to us as terminated by the ugly root at one extremity, or pole, and by the beautiful inflorescence at the other-an arrangement in which all symmetry seems set at defiance. Now, why is this? Why are the flower and fruit always produced at the upper extremity of the stem, a position which (besides its disregard of symmetry) can be reached only after the

* Read before the Botanical Society, 13th December 1860.

plant has survived all accidents till near the close of life, and when one would suppose that its vital energy must be nearly exhausted, and the plant consequently little fitted for accomplishing this, which is nevertheless the most critical and the most important function of animated nature?

The only explanation which I have seen of this phenomenon, and others of a similar nature, consists in references to the condition of vegetable life at different periods of growth, these being again referred to the season of the year, or some external influence. But it is precisely the condition of vegetable life at different periods of growth which is wanted to be explained. Life, at every epoch in the development of the plant, is no doubt always co-ordinate with the work which it has to do at the time, alway adequate to accomplish the development proper to that epoch, if the environments of the plant fulfil their part. But this fact does not explain why the development of the plant is what it is, and not otherwise. The insufficiency of such a view, as also its plausibility, is, I think, well shown by the point in hand.

The terminal position of the fructification, it is said, is owing to the exhaustion of the vital energy of the plant, and the flower is, notwithstanding its beauty, the expression of exhausted energy. And in favour of this view it is, moreover, argued, with seeming cogency, that when the branch of a fruit-tree is injured, or a plant made to grow in a poor soil, it gives flower buds, whereas if it had been left free from injury, or had been grown in a rich soil, it would have given leaf buds only. And the entire explanation is closed by an appeal to what is indeed a beautiful provision in the economy of nature, viz., that when the life of the individual is in danger, an effort is made to develop the reproductive apparatus, so as to secure the life of the species, should the individual perish. Now, such an explanation seems to have everything in its favour. At first sight it seems wholly satisfactory. But it is only at first sight. Many things soon present themselves which are against it. Thus in the higher regions of the animal kingdom, those which are analogous to the region of flowering plants in the vegetable kingdom, it is found that the reproductive apparatus attaches to the period of highest physical

power and earliest maturity of form. In all the more perfect animals, the appearance of the reproductive organs in force rather anticipates the epoch of the complete development of the individual form than lags behind it till the close of life, when the vital energy is expiring, as it is said to do in reference to flowering plants. And this, too, although the organs of reproduction in animals are of very humble pretensions compared with many of their other organs, and such that it seems as if they might easily be developed at any time, however late in life, while those of plants, on the other handtheir blossoms-are so elaborate and beautiful, that they are judged by every unsophisticated observer to be the most exquisite products of vegetable nature, and certainly everything about them points to the inference that, instead of being products of an exhausted system, vegetation culminates towards their production, and bestows its highest energies in their development. It is, indeed, true that in many of the lower animals (as is familiarly exhibited by the silkworm, for instance), the reproductive power does not appear until the individual has gone through all the phases of its existence, and, as may be said, has nothing else left for it to do but to die. But it were more cogent in this case to say that the reproductive apparatus does not make its appearance till the moth appears, because it is necessary that the individual should complete its metamorphoses, and attain its full development, before it is allowed to proceed to the formation of embryos, whose part is to develop and reproduce all these metamorphoses. That the appearance of the reproductive apparatus at the time referred to cannot be ascribed to exhausted life, is clearly proved by this, that if that apparatus be not allowed to discharge its function, the life of the individual will be indefinitely postponed -postponed till the ungenial influence of external agencies force it to die. In such cases, in fact, as in all others of the same order, it were nearer the truth to say that the highest flow of life and of the organism is bestowed in developing the reproductive apparatus, and that in this apparatus vital energy is in a peculiar manner stored up, rather than to regard the development of that apparatus as an evidence and a product of exhausted energy.

As to the beautiful fact invoked above to sanction the theory of exhaustion-viz., that injury or deficient nourishment tends, in vegetable nature, to give flower-buds instead of leaf-buds-this fact, when scientifically interpreted, merely affirms that when a plant or tree is hurt or starved where it is now growing, so that it would be improvident to increase its bulk in that place, the buds, which, had the plant been in health, and in a rich soil, would have given indefinite branches, or an extension of the individual (for a leaf-bud is an indefinite branch-bud), are so modified as to bring the branches to a close; for such is the undoubted function of flower-buds. In other words, the formation of flower-buds instead of leaf-buds, in the circumstances described, only shows that the circumstances of injury and starvation are met, on the part of the vegetable economy, by an arrest of the individual thus exposed to hurt and hunger. That this arrest should secure also the development of that apparatus by which the individual plant may change its locality, or, as is commonly said, by which a future individual may be provided, and the species preserved, and the end of locomotion attained where the faculty is not bestowed by the gift of limbs, is indeed an example of that wisdom and goodness which underlie all nature, and bespeak its origin; but that wisdom is never manifested in resorting to expedients to prevent worse, as we, through our weakness, are so often obliged to do. In Nature, all is manifestation of Divine law, not only in its final, but also in its formal and its physical cause. Let it be granted that, to account for the appearance of the reproductive organs in plants when their life is threatened or nearly over, the final cause has been rightly assigned when it has been shown that, by this arrangement, the race is saved when the individual perishes, still the formal, the physical cause remains to be discovered. The doctrine of exhaustion will not do.

I now proceed to give another explanation, which to me at least seems satisfactory, because it both accounts for the terminal inflorescence, and refers this phenomenon to a general law, a law of acknowledged dominion in Nature, and in fact the foster-mother of her whole economy, and of the entire life and development of the plant. I am bent on showing that