xviii INTRODUCTION. 



tinuous, membranous, branched tubes, to receive, contain, and direct the 

 nutritive juices, from the organs where they are prepared, till they are 

 required for the purposes of nutrition, respiration, or the secretions. 

 5. The glandular tissJte includes those secreting organs which pro- 

 duce fluids for internal use, or to transmit them out of the body, by 

 means of excretory canals. These organs have a granular or lobated 

 form. 6. The bony tisstie, or cartilaginous, calcareous, and corneous, 

 is formed by the mucous, or gelatinous parenchyma, in which are 

 deposited the hardest and most resisting parts, which protect the body 

 and contribute to its motion. 7. The fibrinous or muscular tissue is 

 composed of filaments disposed in bundles, which, from their power of 

 contraction, produce all the movements which characterize animals. 

 8. The nervous tissue is a net-work of filaments and tubes, in the 

 interior of which are found prolongations of the cerebral matter. 

 This tissue, extending from the centre to the circumference, like radii 

 from a centre, is the medium of sensation, — actuates every member 

 through the medium of volition, and connects all the parts of the body 

 by a mutual sympathy. 



The nmrnaX fluids are found in the body under the form of gases, or 

 liquids, of various consistence. The first being absorbed, or exhaled, 

 are but momentarily under this form. The fluids are the chyme, the 

 chyle, the lymph, the blood, and the serous, albuminous, mucous, 

 saline, and other humors, peculiar to different parts of the body. 



The simple chemical elements which are found in the animal struc- 

 ture, are among the imponderable agents, caloric, light, and the 

 electric fluids. Among the simple gases, azote, which enters into the 

 composition of many of the tissues ; hydrogen, which is one of the 

 elements of lymph, bile, &c. ; oxygen, which all animals absorb in 

 the act of respiration ; carbon, lime, sulphur, iron, &c., which serve as 

 the base of many salts, formed by carbonic and phosphoric acid. 



The instincts and habits of the different classes of animals will be 

 hereafter detailed, in the descriptions of the individual species, whose 

 manners have been most accurately observed. It is sufficient, in this 

 place, to state, that all their motives to action, their migrations, and 

 their instincts, may be traced to the desire of self-preservation, and the 

 impulse of reproduction. 



The Vegetable Kingdom is sufficiently distinguished from the 

 animal, as before remarked, by its passive character, by the want of 

 spontaneous motion, and of sensation. Vegetable life is, therefore, 

 supported by absorption ; and its functions, like those of animals, are 



