GROW TH OF FUNGI AND OF INFUSORIA. 337 



Many fungi grow without light, and in their growth and life 

 are characterized by all the phenomena which characterize ani- 

 mal life ; they destroy air by absorbing oxygen and evolving 

 carbonic acid, and, in a chemical point of view, behave like ani- 

 mals without motion. (See Appendix to Part It.) 



In opposition to this class of beings, which can scarcely be 

 designated as plants, we have living creatures endowed with 

 motion, and with the organs which characterize animals, and 

 yet which behave in the light like green plants ; for while 

 they increase in size and number, they furnish sources of oxy- 

 gen when its access, in the form of air, is excluded or prevented. 



16 



