550 FACIAL ANGLE:-SPECIAL ENDOWMENTS OF MAN. in the different species of the Monkey tribe, it varies from about 65° to 30° (fig. 293); and as we descend still lower, we find it still more acute. In the Horse and Boar, for example, it becomes impossible to draw a straight line from the fore head to the upper jaw; in consequence of the retreating character of the former, and the projection of the nose; this will be evident from an examination of fig. 294. In Birds, Reptiles, and Fishes, the facial angle, when it can be measured, is found to be still further diminished. 721. It appears, then, that the mind of Man differs from that of the lower animals, rather as to the degree in which the reasoning faculties are developed in him, than by anything peculiar in their kind. Among the more sagacious Quadrupeds, it is easy to discover instances of reasoning as close and prolonged as that which usually takes place in early childhood; and it is only with the advance of age and the maturity of the powers, that the superiority of Man becomes evident. The foundation of this superiority lies in the power of self-direction and self-improvement which Man possesses. No race among the lower animals ever exhibits a spontaneous tendency to the elevation of its mental powers. When placed under new circumstances, and especially when subjected to Human training, the domesticable races acquire new capacities; and individuals frequently display a very extraordinary degree of sagacious appreciation of matters quite foreign to their natural habits of life. But neither in races nor in individuals are these powers transmitted from one generation to another, when, left to themselves, they return to anything like a state of nature. In Man, on the other hand, the power which every rightly-constituted and rightly SPECIAL ENDOWMENTS OF MAN. 551 trained individual possesses (§ 525) of fixing his attention upon any particular object of consciousness, to the exclusion of all others, becomes the source of the highest and most enduring intellectual advancement, and of all moral improvement. It is in virtue of this power, that he is not only enabled to profit largely by the acquired knowledge of others, but that he comes to possess a moral responsibility for the use he makes of his faculties, which cannot be predicated of beings whose succession of ideas is entirely determined by impressions made from without. 722. There is another attribute, moreover, by which Man seems to be distinguished from all other animals; namely, that disposition to believe in the existence of an unseen but powerful Being, which seems never to be wanting (under some form or other) in any race or nation, although (like other natural tendencies) it may be defective in individuals. It requires a higher mental cultivation than is commonly to be met with among savage races, to conceive of this Power as having a spiritual existence; but it appears, from the reports of Missionaries who have laboured to spread Christianity amongst the Heathen, that an aptitude or readiness to receive this idea is rarely wanting; so that the faculty is obviously present, though it has not been called into operation.-Closely connected with this tendency to believe in a Great unseen Power, is the desire to share in His spiritual existence, which seems to have been implanted by the Creator in the mind of Man, and the existence of which is one of the chief natural arguments for the immortality of the soul, since it could scarcely be supposed that such a desire would have been implanted, if it were not in some way to be gratified. Such views tend to show us the true nobility of Man's rational and moral nature, and the mode in which he may most effectually fulfil the ends for which his Creator designed him. We learn from them the evil of yielding to those merely animal tendencies,-those "fleshly lusts which war against the soul," that are characteristic of beings far below him in the scale of existence, and tend to degrade him to their level; and the dignity of those pursuits, which, by exercising his intellect, and by expanding and strengthening the higher part of his moral nature, tend to raise him towards the perfection of the Divine Being. 552 TWO PRINCIPAL MODES OF REPRODUCTION. OF CHAPTER XV. REPRODUCTION. 723. THERE is no one of the functions of living beings, that distinguishes them in a more striking and evident manner from the inert bodies which surround them, than the process of Reproduction. By this function, each race of Plants and Animals is perpetuated; whilst the individuals composing it successively disappear from the face of the earth, by that death and decay which is the common lot of all.—A very unnecessary degree of mystery has been spread around this process. It has been regarded as one altogether inscrutable, whose real nature could not be unveiled, even by the scientific inquirer, and whose secrets the uninitiated should never seek to comprehend. But so much light has been thrown upon it by recent investigations, that we now know at least as much of this, as of almost any other function; and the Author's experience has led him to believe that such knowledge may be communicated to the general reader, without the least infringement of the purest delicacy of feeling. In his own judgment, indeed, it is far better to afford a legitimate satisfaction to the curiosity which naturally exists upon the subject, than, by refusing all information, to drive the inquirer into objectionable methods of gratifying it. 724. It has been elsewhere shown (VEGET. PHYS., Chaps. IX., XII.), that, in the Vegetable Kingdom, there are two distinct modes by which the propagation of Plants may take place ;-the extension of the parent structure into new portions, which, being independent of it and of each other, can maintain their lives when separated from it;—and the origination of a new being by the concurrent action of two sets of cells set apart for this special function, and designated "sperm-cells" and "germ-cells." The bodies of the first class are known as leaf-buds or gemma in the Flowering Plants, and sometimes also among Cryptogamia, some of which last, as the Marchantia (VEGET. PHYS. § 757), are furnished with a peculiar means of producing them; and it appears from recent investigations that the " spores of Ferns, TWO PRINCIPAL MODES OF REPRODUCTION. 553 Mosses, and Hepaticæ, as well also the "zoospores" of Algæ, belong to the same class of reproductive bodies. The gemmæ of Phanerogamia may be developed in connexion with the parent structure, and may continue to form a part of it; or they may be removed from it (as in the processes of budding, grafting, &c.), and may be developed into new individuals. On the other hand, the bodies of the second class are known as seeds among Flowering Plants; among the Cryptogamia they present a variety of forms. From the very first, these are destined to produce new individuals; and although they are often assisted in the early stage of their development by the parent, they are its true offspring, rather than (like gemmæ) extensions of itself. Both these modes of Reproduction, namely, gemmation and sexual generation, exist in the Animal Kingdom; but the former is confined to its lower tribes, among which we often find it exercised in very remarkable modes. Gemmiparous or Non-Sexual Reproduction. 725. Among Infusoria (§ 133) we find the process of gemmation, or of fission, which is a modification of it, to be almost the only ostensible means of propagation which the beings composing that wonderful group possess. The former may be continually witnessed by the microscopic observer in the common Vorticella, a bell-shaped animalcule attached by a stalk Fig. 295.-VARIOUS FORMS OF ANIMALCULES, some of them undergoing spontaneous fission. (fig. 295, a, a), and abundant in almost every pool in which aquatic vegetables grow, especially clustering around the stems of Duckweed; and its various stages closely resemble those 554 GEMMIPAROUS REPRODUCTION OF LOWEST ANIMALS. which have been already described (§ 122) in the Hydra. But not unfrequently in this species, and ordinarily in many others, the body divides into two equal parts, in each of which we see a mouth and other parts resembling those of the original. This division is gradual. A narrowing of the body along or across its middle (for the fission or cleavage sometimes takes place lengthways, as at b, sometimes transversely, as at c), is first seen; the indentation at the edge becomes gradually deeper, and at last the two parts hold together by but a narrow band, which finally breaks, and they become free. The same method of multiplication is observed among the simple Rhizopoda (§ 129); but when the gemmæ remain connected with each other, as in Zoophytes, we have such composite fabrics as are presented to us in the classes of Foraminifera (§ 131) and Sponges (§ 136). 726. Reproduction by Gemmation is most characteristically seen among the Radiated classes; and in none better than in the Hydra already so frequently referred-to. Although this interesting little animal sometimes reproduces itself by true sexual generation (§ 734), yet its usual mode of propagation is by buds (§ 122), as shown on the left hand side of the accompanying figure (fig. 296). And, as already explained, it is by this same process of gemmation that the arborescent structures of the Composite Zoophytes are formed; the gemmæ not detaching themselves, but remaining as parts of the common stock (§§ 124,127). In some of those, however, which are formed upon the plan of the Sea Anemone (§ 126), the multiplication (fig. 297) is effected rather by fission or division into two equal parts (as among Infusoria), than by the out-growth of buds. We have already had occasion to notice (§ 125) the very remarkable form of gemmation that Fig. 296.-HYDRA (attached to duck- takes place among Zoophytes, giv weed): one of them developing buds. ing origin to independent beings which seem to belong to a class altogether different, but which |