OF NATURAL HISTOIIT. IS 



night, In fuch a manner that each pair feem to be one leaf 

 only. The leaves of the white lupine, in the ftate of fleep, 

 hang down, and prote<Sl the young buds from being injured 

 by the nocturnal air. 



Thefe and iimilar motions are not peculiar to the leaves of 

 plants. The flowers have alfo the power of moving. Da- 

 ring the night, many of them are inclofed in their calixes. 

 Some flowers, as thofe of the German fpurge, geranium 

 ftriatum, and common whitlow grafs, when afleep, hang their 

 mouths toward the earth, to prevent the noxious effects of 

 rain or dew. 



The caufe of thofe movements which conftltute the fleep 

 of plants, has been afcribed to the prefence or abfence of the 

 fun's rays. In fame of the examples I have given, the mo- 

 tions produced are evidently excited by heat. But plants 

 kept in a hot-houfe, where an equal degree of heat is pre- 

 ferved both day and night, fail not to contracSl their leaves, 

 or to fleep, in the fame manner, as when they are expofed to 

 the open air. This fact evinces, that the fleep of plants is 

 rather owing to a peculiar law, than to a quicker or flower 

 motion of their juices. 



A ftomach and brain have been reckoned eflential charac- 

 teriftics of the animal ; and plants are faid to poflefs nothing 

 analogous to thefe organs. But the polypus has no fl:omach ; 

 or rather, like vegetables, its wdiole body may be confidered 

 as a ftomach. Its internal cavity contains no vifcera ; and, 

 when this animal is turned outflde in, it fl:ill continues to Hve, 

 and to digeft its food, in the fame manner as if it had receiv- 

 ed no injury. The mode by which plants are nourifhed is 

 extremely analogous. They imbibe food by the roots, the 

 trunk, the branches, the leaves, and the flowers. Inflead, 

 therefore, of having no ftomach, their whole ftrucSture is 

 ftomach. With regard to the brain, the polypus, and many 

 ©ther infeds, are deprived of that organ. Hence neither 



