^ 



r 



.1. 



4. 





ence 



cation 



s 



ere 



Jicolor, 



of the 



months 

 s vege- 



pulmo- 

 5 vlfible 

 le fame 

 ^e veins 



eared to 



uid was 



lous on 

 /hich is 



reins on 



ith fcif- 

 .rface of 



)iratioK5 

 • arteries 



furfaces 



nce 



the 



herH) 



as 



b.) ^^'! 

 ves 



dry 



air 



0^ 



Sect. IV. II 



AND VEINS 



45 



water, 



npears in the experiment of monfieur Bonnet, (Ufage des 



Fevilles) ; hence fome aquatic pla 



the water-lily (nymphaea) 



have the lower fides of their leaves floating on the water, while the 

 upper furfaces remain dry in the air. 



This repuhion of the upper furfaces of the leaves of aerial plants 

 to water bears fome analogy to the renitency of the larinx to the ad- 

 miffion of water into the lungs of animals ; 



for if 



fi 



ngle d 



op 



cidentally falls into the windpipe, a convulfive cough is induced 



5"'6 



tated 



For the fame reafon feveral plants clofe together the 



pper furfaces of their leaves wh 

 1 their fleep during the nig 



in 



th 



fame 



ht 



mimofa, the fenfitive plant, and 



the young fhoots of chick-weed, alfine; and of kidney-bean 



feolus 



As thofe infecls which have many fpiracula, or breathing apertures^ 



I 



wafps and flies, a 



immediately fufFocated by pou 



oil 



upon 



them, in 



year 



783 I carefully 



ed with oil the furfaces of 



feveral leaves of phlomis, of Portugal laurel, and balfams ; and though 

 it would not regularly adhere, I found them all die in a day or two, 

 which fliews another flmilitude between the lungs of animals and the 

 leaves of vegetables. 



There is an ingenious experiment of M. Bonnet, (Ufage des feu- 



illes) which (hews that the upper furfaces of leaves exhale much lefs 

 than their under furfaces. He put the flalks of many leaves frefh 

 plucked from trees 



water 



or herbaceous plants into glafs tubes filled with, 

 of thefe he covered with oil or varnifli the upper furface of 



many leaves, and the under furface of many others, and uniformly 

 obferved "by the water finking in the tubes that the upper furfaces 

 exhaled much lefs than half the quantity exhaled by the under fur- 

 faces, w 

 pofes. 



II. I. There exifts a ftrid analogy between the leaves of aquatic 



L 



plants, which are conftantly imraerfed beneath the water, and the gills 



hich (hews them to be organs defigned for different pur- 



3 



of 



\ 



