able kingdom. Most of these are of a soft texture, as the Polypus, so well known from its being capable of existing when turned inside out, and of reproducing any part of its body when destroyed by accident. To this class belongs the Sponge, and the numerous families of the Coral. 3. The mammalia are placed at the head of the animal kingdom; not only because it is the class to which man himself belongs, but because it also enjoys the most numerous faculties, the most delicate sensations, the most varied powers of motion, and the highest degree of intelligence. 4. The peculiar characters of these different classes must be learned from works which treat especially of Comparative Anatomy. It will be proper, however, in this place, to point out some of the peculiarities which distinguish man. 5. In structure and external shape, man bears considerable resemblance to some varieties of the ape tribe, particularly the ourang outang. But we find his position to be upright; his foot is large, and the leg placed vertically upon it; while the toes are short and but slightly flexible, and the great toe is horizontal with the others, so that his feet is well adapted to support the body, but cannot be used for seizing or climbing. Apes have thumbs both upon their hands as well as feet, so that they can seize with both equally well. The head of man is also very large and heavy, owing to the magnitude of the brain, and the smallness of the cavities of the bones; yet the means of supporting it, except in a perpendicular position are very small, as the ligament of the neck, which in quadrupeds is very thick, in him is almost wanting. 6. Besides this, the spinal column is so constructed, that its flexure forwards is not prevented, so that should he attempt to walk on all-fours, his mouth and eyes would be directed towards the earth, and he could not see before him, while in an erect attitude he preserves the use of his hands, and at the same time his organs of sense are most favorably situated for observation. 7. Though man surpasses all other animals in dexterity, yet there are many that exceed him in strength, swiftness, and the acuteness of many of the senses. The eagle excells him in acuteness of vision, the grey hound in delicacy of smell, and a vast number of animals in strength, yet reason makes up for all other deficiences. Though physically defenceless, yet the whole brute creation is subjected to his control. But 8. It was formerly supposed that man, because gifted with the highest mental endowments possessed the largest of all brains. But as elephants and whales surpass him in this respect, and the sagacious monkey and dog have smaller brains than the comparatively stupid ass, hog, and ox, the opinion was relinquished, and man was said only to have the largest brain in proportion to the size of his body. more extensive observation proved that canary and other birds, and some varieties of the monkey tribe, have larger brains than man in proportion to the body, and several mammalia to equal him in this particular; and as rats and mice too, surpass the dog; horse, and elephant in the comparative bulk of their brains; this opinion gave way to the one now generally adopted by physiologists, viz. that man possesses the largest brain in comparison with the nerves arising from it. 9. In consequence of the great size of his brain, man has a larger facial angle, which is the space included by lines drawn from the centre of the ear to the root of the nose, and from thence to the forehead. In the best formed human heads, this angle is equal to 80 or 90 degrees. In man also, the chin is more prominent, and the lower front teeth more perpendicular; his teeth also are of the same length, which is not the case in the inferior animals. Man only can adapt himself to the great varieties of climate, and of food, which exist on the surface of the earth. 10. Lastly, man is possessed of faculties that enable him to trace effects to their causes, to distinguish between virtue and vice, to reflect upon events that have passed, to anti cipate the issues of the future; and, above all, to raise his causes, fo mind to the Supreme Intelligence, the cause of leausGTONA whom all nature owes her existence, and to whom, with more or less clearness of conviction, he feels conscious of responsibility. Questions. How is the animal kingdom divided? What is meant by vertebrated, and what by invertebrated animals? How are the vertebral divided? What is understood by a warm-blooded animal? What by a cold-blooded? Into how many orders are the mammalia divided? Birds? Reptiles? What are molluscous animals? What does the articulated class include? What the radiated? What class is placed at the head of the animal kingdom? --and why? What species of animals does man most resemble? How does he differ from the ape tribe? Is man excelled in any respect by the inferior animals? Mention some of the peculiarities of man. CHAPTER III. STRUCTURE OF THE HUMAN BODY. 1. THE human body is composed of solids and fluids. These terms, however, are merely relative. There is no fluid which does not contain some solid matter in solution; and no solid however dense, which does not contain some fluid. The nature of both fluids and solids is essentially the same, for we see one readily passing into the other; indeed no fluid long remains a fluid, and no solid a solid; but the fluid is constantly passing into the solid, and the solid into. the fluid. . 2. The relative proportion of the fluids in the human body much exceeds that of the solids, the excess being about 8 to 1. But the excess varies according to the age. The younger the age, the greater the preponderance of the fluids. As age increases, the fluids gradually diminish, till in old age, they become so much lessened, that the body assumes a dry, wrinkled, shriveled and stiff appearance. In this manner we explain the softness and roundness of the body in infancy and youth, and its hard, unequal and angular surface in advanced life. 3. The fluids, then, are very important, as they furnish. not only the material out of which every part of the body is formed, but they also furnish the medium by which the noxious and useless matter is carried out of the system. Every part of the body is a laboratory in which complicated and transforming changes are constantly going on; the fluids are the materials on which these changes are wrought, and the vital forces are the agents by which they are effected. The fluids either contribute to form the blood, or they constitute the blood, or having performed some special office, as moistening the various surfaces, are returned to the blood; hence according to their nature, they are called aqueous, albuminous, mucous, serous, &c. 4. The solids are composed of the same chemical principles as the fluids, and by analysis are reduced to the same ultimate elements. In the formation of solids, the particles of matter are supposed to be arranged in one of two modes, viz., either in the form of minute threads or fibres, or of thin plates or laminae; hence every solid of the body is said to be fibrous, or laminated. These fibres, or laminae are variously interwoven, and interlaced, so as to form a net-work; and the spaces included between them are called areolae, or cells. According to some microscopical observers, the ultimate animal solid is a minute sphere or globule of matter, not exceeding an eighth thousandth part of an inch in diam eter. 5. The fibrous or laminated matter is often so arranged as to form a structure, possessing distinct and peculiar properties; and each of these modifications is considered a separate form of organized matter, and is called a primary tissue. These tissues have been variously classified by different anatomists and physiologists, some making them to consist of five, viz., the membranous, the cartilaginous, the osseous, the muscular, and the nervous; while others make but three, the cellular, the muscular, and the nervous. Another arrangement is into filaments, fibres, tissues, organs, apparatuses, and systems. 6. A filament is made up of a series of minute or primi. tive molecules, arranged in a row. A fibre is composed of several of these filaments united together, as the muscular and nervous fibres. A tissue is supposed to be composed of fibres disposed in planes, forming in this manner an expansion, or when crossing each other, forming spongy solids, with cells interspersed throughout. In this way are the cellular, serous, and mucous membranes formed. When |