"Indeed, life has been an improving gift from my youth; and one reason I believe to be, that my youth was not a happy one. I look back to no bright dawn of life which gradually 'faded into common day.' The light which I now live in rose at a later period. A rigid domestic discipline, sanctioned by the times, gloomy views of religion, the selfish passions, collisions with companions perhaps worse than myself, these, and other things, darkened my boyhood. Then came altered circumstances, dependence, unwise and excessive labors for independence, and the symptoms of the weakness and disease which have followed me through life. Amidst this darkness it pleased God that the light should rise. The work of spiritual regeneration, the discovery of the supreme good, of the great and glorious end of life, aspirations after truth and virtue, which are pledges and beginnings of immortality, the consciousness of something divine within me, then began, faintly indeed, and through many struggles and sufferings have gone on. "I love life, perhaps, too much; perhaps I cling to it too strongly for a Christian and a philosopher. I welcome every new day with new gratitude. I almost wonder at myself, when I think of the pleasure which the dawn gives me, after having witnessed it so many years. This blessed light of heaven, how dear it is to me! and this earth which I have trodden so long, with what affection I look on it! I have but a moment ago cast my eyes on the lawn in front of my house, and the sight of it, gemmed with dew and heightening by its brilliancy the shadows of the trees which fall upon it, awakened emotions more vivid, perhaps, than I experienced in youth. I do not like the ancients calling the earth mother. She is so fresh, youthful, living, and rejoicing! I do, indeed, anticipate a more glorious world than this; but still my first familiar home is very precious to me, nor can I think of leaving its sun and sky and fields and ocean without regret. My interest, not in outward nature only, but in human nature, in its destinies, in the progress of science, in the struggles of freedom and religion, has increased up to this moment, and I am now in my sixtieth year."- Memoirs, Vol. III., pp. 412-414. His life was eminently useful and beautiful. He died in good season, leaving a memory that will long be blessed. It remains for us to say a word of the "Memoirs." The work is well done, by a kindred and a loving hand. The Memoirs only are published, however, the Life yet remains to be written. Some things are passed over rather hastily by the Edito; we should have been glad if he had told us more of Dr Channing's relations to the theological parties of his time, especially to his own sect in his later years; if he had shown us more in detail with what caution and slowness he came to his liberal conclusions. As a whole, the picture wants a background, and also shadow. But, on the whole, the work is well and faithfully done, though it does not give us so complete and thorough a view of the man as the Memoir of Henry Ware offered of that lamented and sainted minister. An index would be a welcome addition, but, as one seldom finds that in an American book, we will not make a special complaint. ART. III. - Principles of Zoology: with numerous illustrations. For the use of Schools and Colleges. Part I. Comparative Physiology. By Louis Agassiz and Augustus Á. Gould. Boston: Gould, Kendall, and Lincoln. 1848. 12mo. pp. 216. "As the spirit of language," says Oken, "is not to be understood from ordinary Grammar, and a natural system of words and of language can be attained only in Philosophical Grammar, so called, so, also, the present natural method in Zoology is not the true system. It only arranges materials, as an architect, before commencing a building, piles stones on stones, mortar on mortar, sand on sand, beams on beams, laths on laths, and bricks on bricks, in order afterwards, by separation and new combination of the various elements, to form a habitable dwelling. In the same way Zoology must proceed, in order really to arrange animals as Nature has arranged them; that is, besides their structure, it must comprehend the laws of their affinities, and their rank, which is possible only by tracing the history of their development. The true natural system must, therefore, be a system of development, a genetic or physiological one, a problem on which many are now at work, the solution of which, however, is not to be expected as yet." It is a great point gained when naturalists of the standing of Agassiz and Owen in empirical science acknowledge the importance of this principle. It is necessary, certainly, first of all, that facts be collected, and there will perhaps always be men, and not the least intelligent and devoted, who will apply themselves exclusively to this, and see no interest beyond it. But at the same time it is not less true that the whole value of the facts for Science consists in their ulterior meaning and application; and that one fact is as good as another and as good as a thousand, if we do not go beyond the facts and determine what their value, their position, and their affinities are. The importance of this higher application is acknowledged at the outset, in the work before us. Thus, § 2: "Animals are worthy of our regard, not only when considered as to the variety and elegance of their forms, or their adaptation to the supply of our wants; but the Animal Kingdom, as a whole, has also a still higher signification. It is the exhibition of the divine thought, as it is carried out in one department of that grand whole which we call Nature; and, considered as such, it teaches us the most important lessons." It is (§ 501 et seq.) the development of a divine plan in the Universe, by which all the classes and divisions of animals are connected together and to the rest of the world, not by material ties only, by descent, or as the necessary condition for supporting life, but by a "link of a higher and immaterial nature. And we are warned (§ 16) to bear in mind the distinction between the analogies of animal organs or parts, - the external resemblances of function or purpose, as it were, necessitated by similarity of the outward circumstances in which animals of various classes are placed, and affinities or homologies, which are the inward relationships caused by identity of plan, but often obscured by dissimilarity of form or use. Thus there is an analogy between a bird's wing and that of a butterfly, both serving for flight. But no affinity, since they differ entirely in their anatomical relations. "On the other hand, there is an affinity between the bird's wing and the hand of a monkey, since although they serve for different purposes, yet they are constructed on the same plan." This plan is pointed out in the parallelism and universal connection shown in the development of the various animal systems; of the individual animal, in his growth from the egg; and of the animal kingdom in its distribution and geological succession. The nervous system, as the grand characteristic of animals, is the first developed in the embryo, and is the invariable accompaniment of animal life. The lower animals, which, throughout, we shall find characterized by a feebler individuality, show this also in their nervous system, which is scarcely divided into separate nerves. All the special senses, except Touch, are wanting in the Radiates and Mollusks; some of them have rudimentary eyes, which, however, do not see, and are homologous but not at all analogous to the eyes of higher animals. As we ascend in the scale the other senses successively appear in parallel perfection. The ear, from a single expansion of the auditory nerve on a sac excavated in the cartilage of the head, as in the cuttle-fish, or even placed on the legs, as in the grasshopper,- becomes more and more complicated in its apparatus. No organ of Smell has been found in any of the Invertebrate animals, and Taste scarcely exists except in the Mammals. Voice is confined to the Mammals, the Birds, and the Frogs. The power of voluntary motion, belonging also to the nervous system, is common to all animals, but there is the same gradation in the perfection of the apparatus. The lower animals in general employ the whole body in locomotion; in some, organs belonging to other systems are employed, as those of Respiration. It is only among the Vertebrates that locomotion is accomplished by special organs. Among them there is but one plan, the idea of all the members, as it were, being introduced at once, though at first as a germ, progressively developed. Thus, the pectoral fin of Fishes is a hand at the shoulder, the arms being withdrawn into the body, just as it is in the embryonic state of higher classes. The hand, however, is not yet distinctly organized, but broken into an irregular multitude of rays instead of fingers. -the Connected with the nervous system is its support, the skeleton, which properly exists only in the Vertebrates, hard parts in the lower animals being homologous only to the skin, hair, &c., of the higher, and not appropriated to the nervous system. The whole of the vertebral skeleton is reducible to one type-a central cavity enclosing the central nervous mass, and various processes which, in some cases, form members. This type is represented by the single vertebræ, each of which combines all the essential parts of the whole frame, though only in rudiment. Thus the skull is only a collection of expanded vertebræ; the ribs, highly developed spinal processes, and the limbs free ribs. In the lower animals, Nutrition, Respiration, and Circulation are confounded together. (Ch. 6.) The Polyps have only a single cavity for digestion, &c., and the circulation of the water and the substances which it contains, within this cavity, is nutrition, respiration, and circulation at once. From these there is the same progression to the Mammals, which alone, (218) properly speaking, masticate their food; showing in other respects, also, the highest complication and perfection of apparatus and function. The harmony of each organ with the whole animal is strikingly displayed in the teeth, a single molar being sufficient to determine the animal. Circulation, where it begins to be distinct, that is, where there is a heart, is at first irregular, the heart contracting only occasionally; the heart itself being a mere sinus in the artery. At first, in the embryo, and in some lower animals, there are no veins, the blood finding its way back to the heart without vessels. Afterwards, in the Crustaceans, there is a double set of vessels, but the blood is mixed as soon as it enters the heart. In the Reptiles there is the beginning of a separation of the heart, but still the venous and arterial blood are not kept separate. Respiration is oxygenation of the blood. This in the Polyps is accomplished by the circulation of water into the body. In Insects air pervades the body in minutely ramified vessels, Respiration being still somewhat confounded with Circulation. Possibly allied to this, though with other functions also, is the penetration of water, in minute vessels, to every part of the body of aquatic animals, a curious arrangement recently observed in various of our fishes by Professor Agassiz. A trace of it is seen in the great degree to which air penetrates the bodies (even the feathers and bones,) of Birds. As we rise in the scale from the Polyps, we find a special organ devoted to Respiration; at first outside, as in some Worms and Mollusks, then covered, as in Fishes, and finally within the body. Reproduction in the Animal kingdom normally takes place through means of eggs, though some of the lowest types, not entirely distinct from the Vegetable kingdom, propagate by means of buds, (gemmiparous generation,) or by divisions, (fissiparous generation,) which resemble the suckers of plants, only that the individualizing tendency of the animal is shown in the separation from the stock. The egg is formed on the same plan in all animals, from the highest to the lowest, only that in the latter it is more simple, the outward covering, the albumen, being wanting. There is a wonderful identity in essentials between the eggs of the most different animals, and the development of all is the same as far as it goes, though arrested at an earlier stage in some than in others. Yet, in the earliest epochs, each class is appropriately marked. Thus, - |