222 



PHYTOCHEMY. 



leaves. But, in the same manner, they repair their loss of 

 oxygen, by which means new affinities take place, until at 

 last the elementary substances in the blossom separate from 

 one another, from which separation the decay and partial 

 death of this organ take place. 



In this ceaseless circulation, we cannot consider deoxyda- 

 tion as the ultimate object of the chemistry of the vegetable 

 kingdom, especially as a manifest progress to a still more 

 powerful oxydation may often be remarked. It is in this 

 manner, that, by means of the more complete predominance 

 of oxygen, resin is produced from oil, gum from mucilage, 

 and fixed substances from those that are volatile. 



346. 



These general considerations shew us the difference be- 

 tween the composition of animals and vegetables. The diffe- 

 rence evidently consists in this, that azote and hydrogen are 

 the prevailing matters in animal substances, oxygen and car- 

 bon in the vegetable world ; on which account, animal juices 

 commonly putrefy, but vegetable saps pass into a state of fer- 

 mentation. Not as if these matters were confined exclusively 

 to each of the two organic kingdoms, since not only do albu- 

 men and gluten pass into a state of putrefaction, and disen- 

 gage ammonia ; but we have also shewn the evolution of 

 azote and hydrogen from blossoms, and the predominance of 

 both these matters in the pollen. Our concern at present is 

 chiefly with the general difference of composition, which al- 

 ways observes the assigned relations in the two great king- 

 doms of nature. It is hence that in transition forms, and in 

 organised bodies of the lower orders, we usually regard it as a 

 common proof of an animal or of a vegetable nature, if, when 

 the body is burnt, it gives out an animal odour, which arises 

 from a pecular union of azote and hydrogen with carbon. 



