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sion of cell-life, which suffices to designate the course of the humblest and most short-lived being, through its growth, development, decay, death, and reproduction, includes, also, the whole series of phenomena presented by the most elaborate organised body, putting aside those which are strictly chemical or physical. Further than this it would seem impossible for any generalization to carry us. The physical philosopher has his laws of mutual attraction, laws of motion, and other similar comprehensive expressions of facts common to all matter; and it is indifferent to him whether he applies them to masses or to component particles, the laws being the same alike in both. But the existence of such laws is an ultimate fact in his science, of which he can give no other account than by referring it to the will of the Creator. So, in his law of cell-growth, the physiologist has a general fact common to all forms of organised being, under which he is enabled to arrange all the manifestations of life, however complex. Beyond the simple cell, however, he cannot go; for to attempt to separate this into its component elements, would be to destroy its character as an organised body. The atom of matter, whether real or hypothetical, represents the mass, because it has all the properties of the mass; but nothing less than a cell can represent an organised being, the essential idea of whose structure supposes a diversity of parts, and whose peculiar train of actions is destroyed by further division. The cell in Physiology, therefore, is what the atom is in Physics.

It is natural, however, that the physiologist should be asked to account for the diversities in the action of the cells, of which any single organism is composed. Thus he may be expected to inform us, why one of the cells of the embryonic mass develops itself into bone, another into muscle, and another into nerve; or why one set of cells in the adult structure absorbs nutritious matter, another converts it, and a third removes it when it has passed into a state of decomposition. He is constrained to reply, that he can give no reason for this at present; and that it is doubtful whether he will ever be able to furnish one. All that he can say is, that this variety of functions in the cells of a single organism does but repeat the variety which is met with in those elementary forms of vegetable life in which each cell is a complete plant. For instance, that one group of cells in the human body should appropriate bile, another fat, another urea, and so on, is obviously a parallel fact to the production of red colouring matter by the simple Hematococci, of green by the Chlorococci, or of an azotised compound by the Torula cerevisii or yeast-plant. Such phenomena are the elementary facts of his science; of which he can give no other explanation, than the chemist and physical philosopher can give of the different properties of his inorganic elements,-as, for example, why one collection of atoms should possess the assemblage of properties which constitute it potassium, or why another should have the properties comprised under the designation of oxygen, or why these two should have a strong affinity for each other. To have arrived at a set of ultimate facts, so simple and comprehensive in their character as to be entitled to take rank with the ultimate facts of physical and chemical philosophy, is the great triumph of modern Physiology: and for this triumph Physiology is entirely indebted to the microscope, and the skilful use which has been made of it.

We shall not weaken the force of these statements by any commentary of our own. We undertook to demon. strate that the microscope, as an instrument of scientific research, is now fully entitled to take rank with the telescope ; in virtue of its perfection as an optical instrument, of the new facts which it has brought under our cognizance, and of the comprehensive views which it has opened to us.

The grandeur of these views must not be estimated by the space over which they extend, but by the conceptions to which they give rise in our minds. There is something indeed in the extremes of minuteness, which is no less wonderful, we might almost say, no less majestic,than in the extreme of vastness. If the mind loses itself in the contemplation of the immeasurable depths of space, and of the innumerable multitudes of stars and systems by which they are peopled, it is equally lost in wonder and admiration when its eye is turned to the countless multitude of living beings which a single drop of water may contain--to the wondrous succession of phenomena which every individual amongst them exhibits, and to the order and constancy which these phenomena present. Or, still more, when we direct its scrutiny to the penetration of that universe, which may be said to be included in the human body, (and now said with a meaning unknown to those ancient philosophers who first designated it as a microcosm,) and survey the innumerable assemblage of elementary parts, each having its own independent life, yet each working in perfect harmony with the rest, for the completion of their most significant yet most mysterious whole. In the study of the one class of phenomena, no less than in the survey of the other, are we led towards infinity; and in both alike do we discern the orderly, uniform, and effectual ministration of a wise design, evolving the most varied and astonishing results from the co-operation of the most simple means.

ART. II.--THE RACES OF MAN, AND THEIR

GEOGRAPHICAL DISTRIBUTION.

The Races of Man, and their Geographical Distribution.

By Charles Pickering, M.D., Member of the Scientific Corps attached to the United States Exploring Expedition. 4to. London: John Chapman. 1849.

This splendid volume justly claims a place in every public library. Its price puts it beyond the reach of all but the rich, yet the materials which it contains ought to be accessible to all the studious, and will have much to interest even the superficial reader. The volume is in fact only part of a larger work, which contained an account of the Exploring Expedition sent out by the United States, in the years 1838-1842, under the command of Captain Wilkes, U.S.N. His ship was named the Vincennes. Dr. Pickering was associated to the scientific corps, in the capacity of Naturalist, as our own countryman Mr. Charles Darwin to the English explorers in the Adventure and Beagle. Mr. Darwin's peculiar taste and talent lay in Geology, and the sciences which minister to it: Dr. Pickering's attention chiefly rests on Botany, and on the varieties of the Human Species; though Zoology is not entirely thrown out of view by him. To Mr. Agate, a member of the Expedition, we owe most of the characteristic and ably-executed paintings of human specimens, with which this volume is adorned and illustrated. One plate, however, is from Mr. Drayton's pencil, and two from Mr. Prisse, in Egypt and Nubia.

In the course of this five years' voyage, Dr. Pickering visited Brazil, Patagonia, Fuegia, Chili, Peru, California, interior Oregon, various islands of the Northern Pacific, Southern Polynesia, Australia, the Philippines, Singapore, Bombay and the Deccan, Muscat, Mocha, Suez, the valley of the Nile, Zanzibar, Cape Town, St. Helena, Madeira, and the Cape Verd Islands. To condense the results of his researches would be a more elaborate and responsible task than we can take on ourselves, nor do we feel compe

tent to pronounce scientifically on the very difficult problems which he takes in hand. It will suffice to indicate to our readers the direction of his investigations and the character of his work.

Dr. Pickering appears to have no doubt whatever of the original derivation of the whole human race from a single stock, nay, and from a single locality ; in so far that he occupies himself with a scientific inquiry into that locality. He assumes that primitive man must have lived where clothing was unessential and art needless to life; and he finds these conditions in the Equatorial Regions only. Assuming further that no great change in the form of the earth's surface and the distribution of land and sea has taken place since a human population has existed, he inquires from what part of the tropics migrations might take place to people the whole globe, so as to produce phenomena most agreeable to the existing distribution of races. If we understand him (pp. 304, 305), he believes that the geographical problem would most easily be solved by supposing two primitive centres,-one in the East Indies and one in Africa,—whence two different human species diffused themselves : but physiology resists the doctrine of two species, and demands either one only, or certainly not less than eleven. Under this difficulty, he appears to acquiesce in the belief that the islands of the Indian Ocean are the truest home of the human family; where also the orang-utangs abound," which in physical conformation,

“ and even in moral temperament, make the nearest approach to humanity.” Nay, in central Borneo, the realm of the pongo, it is known that a race of actual wild men and women exist, who make nests in the trees, and in external life, as in food, differ little from apes. Their adult males are often shot by the Dayaks, and their females and little ones captured ; and there is no doubt whatever that the race is strictly human.

From the region of Sumatra, Borneo, and New Guinea, the islands of the Tropical Pacific would be gradually peopled. In how very rude a stage of barbarism an art of navigation is attained, adequate to such an enterprize, we are apt to be imperfectly aware. Especially coral-bound shores afford a profusion of animal life for man's support, in water, the temperature of which is delightful to the

CHRISTIAN TEACHER.–No. 47.

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