66 



appointed modes of life, I shall begin with the 

 zoophytes and worms of Linnaeus, and then pro- 

 ceed, in order, through insects, fishes, reptiles, 

 birds and mammiferous animals ; making a few 

 remarks, first, on the organs of each adapted to 

 taking and chewing their food, and to digestion, 

 the circulation of the blood, and respiration ; 

 afterwards passing on to those by which the 

 several functions of smelling, seeing, hearing, 

 tasting and touching are performed, and by 

 which they are enabled to move from place to 

 place. 



In the simplest orders of animals, food is taken 

 by mere imbibition, or suction, without any dis- 

 tinct organ specifically adapted to the purpose. 

 They absorb their nutriment, sometimes without 

 any evident aperture, and sometimes by several 

 such apertures ; and not unfrequently the intes- 

 tinal canal if it may be so called of many 

 individuals communicate together, so as to con- 

 stitute, in fact, but a single animal. Such ani- 

 mals are really so closely allied, both in their 

 appearance and functions, to vegetables, that the 

 line of demarcation between them is not easily 

 defined ; and, fixed as they are, like plants to 

 the soil, or other matters from which they imme- 

 diately and constantly derive their nourishment, 

 any other organs but those of mere imbibition, 

 would have been superfluous to them. But all 

 animals that are unattached to the substances 

 from which they derive their aliment, arid arc 



