,546 INDEX. 



17. Their whole ftruiTtiire may be confidered as a ftomach 

 for receiving their food, 19. Other examples of vegeta- 

 ble movements, 21, 22. Many of them have the power 

 of irritability^ 2 v. Between vegetables and mirierals there 

 is hardly any analogy, 2-1', 25. Analogies between ani- 

 mals and plants, originating from their ftrudkire and or- 

 gans, 25, 35. Sketch of the ilru^ture of plantSj 28, 30. 

 Their oeconomy and functions are refults of a valcular 

 texture, 32. Analogies ariiing from their growth and 

 nourllhment, 34, 40. Food of plants and of anim^als com- 

 pared, 35. Analogies between the animal and vegetable 

 derived from their diiTemination and decay, 40^ &c. Anal- 

 ogies between the eggs of animals and the leeds of plants, 

 46, Some plants may be confidered as viviparous, 47. 

 Plants have their feafons as well as animals, 49. Are all 

 fubjeft to many difeafes, and at lad to individual dilTolu- 

 tion, 51. Of the fuppofed fexes of plants, 25 1 . See fex- 

 es. Pollen or farina of plants, fuppofed to be analogous 

 to the male organs of generation, 252. New varieties of 

 plants often proceed from accidental caufes, 257, 258. 

 Plants, as well as animals, undergo transformations, 309, 

 310. See transformations. Thofe which grow quickly 

 foon perilli, 511. Their longevity, 518. 



Pollen. See plants, and fexes. 



Polypus. Defcription of its ftru6lure and mode of multiply- 

 ing, 28. When cut to pieces in any direction, each fec- 

 tion foon becomes a perfect animal, 29. One fpecies may 

 be engrafted upon another, ibid. Som^e polypi multiply 

 by fplitting longitudinally, and others tranfveriely, 41, 

 Connedls the animal to the vegetable kingdom, 526, 



Probofcis of infects defcribed, 97, 



Propolis, or bee- glue. See bees. 



Puberty. This period of life arrives later, or more early, ac- 

 cording to the difference of fpecies, 38. Of the puberty 

 of animals in general, 269. Changes produced by it, 269 



270, 291. Females arrive fooner at that period than males, 



271. All animals undergo changes at the age of puberty, 

 271. 



Pucerons. Some fpecies are both viviparous and oviparous, 

 44. Can produce without impregnation, 44, 98. Differ- 

 ences between the males and females, 247. Devoured by 

 namberlefs enemies, 389. 



