realm-the hard-working classes-are in pressing need of help now, in this present time. This, I believe, is confessed on all hands, diverse and contradictory as the theories how such help could best be given may be. The question at issue is not whether ameliorations are desirable or the contrary, but in what manner to bring them about, and how to be certain that it is bread which is bestowed, and not a stone. I do not claim to have solved this enigma, or to have invented a millennium. I simply assert my belief that some of my propositions may contain germs capable of being nurtured into hopeful possibilities. As I have selected four principal points in which improvements are required-health, pocket, mind, and amusements-so have I striven to indicate four principal modes which I think best calculated to attain the desired end, and which for the most part must come from without our borders-namely, sympathy, earnestness, money, and centralized organization-all being essential; the last-named especially being so, for it may be regarded as an irrefragable verity that every movement to be really efficacious must be national, and not parochial. I look for many objections on both sides of the temperate zone, on the waters of which alone I elect to voyage. The frigid will aver that I expect too much, that my notions are Utopian and chimerical to the last degree, and the nostrums prescribed empirical and baneful; that it is not to be supposed sensible people will take all this trouble, and rush into such reckless expenditure in a project so visionary. To such my only answer is,-Where the return is to be great the investment must be great also. The torrid, on the other hand, will say I am not sufficiently thorough; that the only means of elevating the poor is by lugging the wealthy down to their level, abrogating dignities, distributing riches, abolishing ownership in lands and corporeal hereditaments. To these my reply will be,-Evil will the day be which shall dawn on such devil's-sabbath employments as these. Levelling upwards is laudable; levelling downwards is execrable. I would in nowise interfere with the least of these institutions. The overthrow of dynasties will not advantage us, nor will a general scramble conduce to our lasting welfare. I am a sceptic as to the benefits to be derived from revolution, although professing myself a warm admirer of reformation, as I understand the word-re-formation. Neither do I anticipate that the time will ever come, under the best devised systems, when poverty will altogether cease out of the land. Evil will there be, and good also, while the world stands. This, however, should be no excuse for indifferentism in the work of lessening the sum-total of the evil, and increasing the sum-total of the good. And so Lazarus unmoors his fragile boat, and launches it, unmanned and untended, on the bosom of the stream,-to meet its fate. HENRY J. MILLER. THE FORMS AND COLOURS OF LIVING CREATURES. IN N the Essay on Animals and Plants, which appeared in the September Number of this Review, the names were given of the principal groups in which the prodigious multitude of living creatures (existing or known to have existed) have been classified by naturalists. It was therein also indicated that these various groups, and all the subdivisions of such groups, are distinguished one from another by variations in the forms and structures of the creatures which compose them. This fact alone would prove that very many differences in form must exist; but, indeed, a very slight knowledge and a very cursory examination of animals and plants would suffice to show this even to any one who knew nothing of the scope or nature of biological classification. In truth, to the non-scientific observer who feels an interest in living things, the difficulty may seem to be rather how to find general resemblances than how to detect differences between creatures which seem so totally diverse as do humming birds from whales, bees from buffaloes, or the numerous African herds of antelopes from the grasses on which they feed. Nevertheless it was pointed out in the second Essay of this series* that all living creatures do agree to a certain extent in the form and structure of their bodies, inasmuch as their bodies are always bounded by curved lines and surfaces, while, if we divide the body of any animal or plant its structure may always be seen to be heterogeneous—that is to say, composed of different substances, even the simplest showing a variety of minute particles (granules) variously distributed throughout its interior. It has also been pointed out† that all living creatures agree in beginning life in the form of a small rounded mass of protoplasm. But all animals and plants further agree in that each kind has its own proper * CONTEMPORARY REVIEW for July, 1879, p. 678. + Loc. cit., p. 704. size, shape, structure, and colour, and each (as we shall hereafter see) shows a positive unity in its fundamental constitution, co-existing with the heterogeneity above referred to. But though each kind has its own proper size, shape, structure, and colour, yet these vary more or less in different individuals, and the degrees of variability are different in different kinds both of animals and plants. As to size, although most living creatures have certain limits which they rarely exceed or fall below, yet many organisms vary greatly in this respect. Thus, that familiar weed, the common centaury (Erythræa centaurium), many vary in height-according to the soil and other external conditions-from half an inch to five feet. As to figure and structure there is more constancy, and the amount of variation which may in these respects be found between different individuals of the same animal species, is generally but slight. In plants and in plant-like animals much greater differences exist as to external configuration; but even in them the internal structure of each species varies but little. Colour is a character which some readers may be disposed to regard as extremely inconstant. We are familiar with many differently coloured varieties of our cultivated flowers; and white black birds, and black leopards are not very uncommon objects. Nevertheless, colour is really a character of much constancy, and is one not only constantly present in different individuals of one kind of plant or animal, but is one constantly present in particular groups of kinds. Thus, for example, all the English plants of the dandelion order which have opposite leaves, have yellow flowers, with the single exception of the eupatory (Eupatorium cannabinum), and whole groups of butterflies are respectively characterized as being blue, or white, or yellow. We have seen that the life of every living being is accompanied by, and may be described as, a series of adjustments of action and structure to external conditions which surround it. Accordingly we may expect to find that the sizes, shapes, structures, and colours of living beings bear relations, which are in very many cases obvious, to their external circumstances, as directly favouring their nutrition, reproduction, or preservation from external injury. Every living creature must be either fixed (like a rooted tree), or capable of spontaneously moving, or of being passively drifted from place to place, and must have a structure and figure suitable to one or other of these conditions. Again, every living creature, whether free or fixed, is either a terrestrial, an aquatic, or an aërial organism; and it may be fitted to live in any two, or even in all three of these conditions—as, for example, is the swan. If terrestrial, it may inhabit the surface of the earth only, or it may occasionally or habitually dwell beneath it. The structure, forms, and even colours of organisms are in most cases plainly adapted to their modes of life in the above respects. Thus, any living creature, which is fixed to the surface of the earth, must either adhere to it by having one side or portion of its body spread out and adjusted to irregularities in the supporting surface, or else by sending prolongations of its substance into the substance of the supporting body, as a plant sends its roots into the soil. Such prolongations, moveover, must (in order to hold fast) either sink deeply or else expand, at a slight depth, into a rounded or discoidal mass, or into radiating processes whereby the whole structure may be securely anchored. We This special modification of form, again, may or may not be accompanied by certain further modifications of structure, according as such rooting parts are to serve, as mere holdfasts, simply for attachment, or (as in most plants) for the absorption of food also. Another modification is also correlated with these conditions. have seen that an interchange of gases takes place between each organism and its surrounding medium. But such interchange cannot take place in the subterranean part of the body, and a corresponding difference of structure between such subterranean part and other parts must therefore obtain. Again, as to colour, we find differences which are evidently related to the different degrees in which different parts of a living body are exposed to the influence of light. Such contrasts notoriously exist, not only between the green parts of plants above the soil and the lighter coloured roots, but between the foliage of a plant which is exposed to sun light and another of the same kind kept in a dark cellar. Many animals which live in permanent darkness are colourless, as, e.g., the Proteus ; but yet this is not an invariable rule, some, as the mole, being of a dark colour. The forms of organisms are evidently often directly related to surrounding influences. A plant or plant-like animal fixed to the soil may be so fixed that light, air, food, friends and enemies can have access equally on all sides or not. Thus, a tree so placed that light and air are excluded on one side, will not grow freely towards that side, but only in directions from whence light and air have access. A coral reef increases much more rapidly towards the open sea (the waves of which bring in food and facilitate gaseous interchange) than towards an adjacent shore. The mere contiguity of parts will often affect the form of organisms. Thus, in many flowers parts which are adjacent become dwarfed, while others which are freely exposed become fully developed, as we see in the flowers of many Umbelliferæ, or plants of the parsley, fennel, and hemlock order. The shapes of flowers bear relation (as we shall see later) to their need for attracting insects which by their visits effect the development of seed, and for repelling others the access of which would be hurtful. The avoidance of enemies may be so effected by an organism that CONTEMPORARY REVIEW for July, 1879, p. 703. + Ibid. for September, 1879, p. 27. their access may be made impossible save in one direction, the extent of vulnerable surface even in that direction being minimized. We have an example of such a condition in those worms which live in calcareous tubes, and which are some of those called "tubicolous annelids."* Again, the medium in which an organism lives-whether aërial or aqueous-has an important relation with its form. A delicate seaweed, the beautifully radiating form of which is a just object of admiration as long as it is supported by its denser natural medium (the sea water), collapses into an amorphous mass when withdrawn thence into the thin air. Obviously a much greater rigidity and strength of structure is needed to support an aërial organism than an aquatic one, unless the former can support itself on other solid structures, such as rocks or trees. In the latter case the form attained may be very elongated and slender, as in the many creeping and climbing plants, which are so often furnished with processes for grasping (tendrils) to aid them in their mode of life. An aërial fixed organism, if it does not rise from the surface of the earth, cannot spread itself very far without developing other points of support-without rooting again. This re-rooting is a familiar phenomenon in many plants, as, e.g., the strawberry. But even a shrub like the common bramble (which is not itself prostrate, but which sends out extraordinarily prolonged branches) is aided by such a process. The ends of its long branches apply themselves to the ground and begin to pierce its surface, the incipient leaves of its terminal bud becoming metamorphosed into roots. An aquatic fixed organism, however, may extend to a very great length, freely floating without effecting any such fresh attachment. Thus the seaweed Laminaria digitatat will spread over a circle 12 feet in diameter, while L. longicornis grows in the form of an elongated riband, from 8 to 12 feet in length and 2 or 3 feet wide. The giant form Macrocystis (with a much more subdivided outline) may extend to the extraordinary length of 700 feet. The conditions under which needful gaseous interchange can be effected and food obtained by different living creatures, govern in various other ways the forms of their bodies. Thus, if it is helpful to the life of a creature to submit as large a surface of its body as possible to the influence of light, or to the action of air or water, then for this purpose its body must be expanded and its expanded parts divided and subdivided as they extend in different directions. It is for this reason that trees branch, and that their branches and twigs divide and subdivide as they do. It is for this reason also that their branches do not grow out one above another in precisely the same direction, but, on the contrary, grow in such a manner that each one may overshadow those immediately beneath as * CONTEMPORARY REVIEW, September, 1879, pp. 33 and 43. |