INTRODUCTION. 11 



tain, 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 tissue in- 

 cludes those secreting organs which produce 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 tissue, or cartilaginous, calcareous, and corneous, is formed 

 by the mucous or gelatinous parenchyma, in which are deposit- 

 ed 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 prolonga- 

 tions of the cerebral matter. This tissue, extending from the 

 centre to the circumference like radii from a centre, is the me- 

 dium of sensation, actuates every member through the medium 

 of volition, and connects all the parts of the body by a mutual 

 sympathy. 



The animal fluids are found in the body under the form of 

 gases or liquids of various consistence. The first being absorb- 

 ed 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 humours peculiar to dif- 

 ferent parts of the body. 



The simple chemical elements which are found in the animal 

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

 the electric fluid. 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 



