150 PROCESS OF NUTRITION. CHAP. III. 



of bogs and marshes is purified, and rendered at 

 least less insalubrious by means of the plants that 

 grow in them, such as the Conferva and Duck-* 

 meat, which last thrives, as he says, better in in- 

 flammable than even in dephlogisticated air. 

 Oroxy- Whatever may be the legitimacy of this conclu- 

 provedby sion, upon the whole the facts from which it is 

 houtz; drawn prove incontrovertibly that plants vegetating 

 in the sun exhale an air purer than that of the at- 

 mosphere. But the air thus exhaled was afterwards 

 ascertained by Ingenhoutz to be pure oxygene gas ; 

 Which is plants then in the process of vegetation inhale 

 during the oxygene gas in the shade or during the night, and 

 d exhale it in the light of the sun or during the day. 



during the $ut the detail and rationale of the different processes 

 remained yet to be inquired into, as also, whether 

 any part of the oxygene inhaled was assimilated to 

 the plant; or whether plants evolve in the day 

 exactly what they inhale in the night. 



Experi- Jt was a t first supposed that plants assimilate the 



roents of 



Saussure. whole, or at least the greater part, of the oxygene 

 they inhale in the night ; but this opinion was soon 

 found to be erroneous, as will appear from the ex- 

 periments of Saussure, whose view of the whole 

 process of the influence of oxygene on the vegetat- 

 ing plant is so full and satisfactory as to leave but 

 little unexplained ; of which view the following is an 

 abstract : a Cactus of six cubic inches in volume, 

 which had inhaled during the night four cubic 

 inches of oxygene, was exposed on the following 



