HOMOLOGY. 79 



kind, nearly in the same manner that a whole 

 language is based upon the twenty or thirty 

 letters of its alphabet. Acids and alkalis, stimu- 

 lants and narcotics, food and poison, and many 

 other wholly antithetical properties, may exist 

 in two substances of absolutely identical compo- 

 sition, except as containing some atoms more 

 or less of a substance in itself perfectly inert. 

 Nay, it is even probable that were our methods 

 of analysis perfect, we might be able to demon- 

 strate that all the elements are ultimately 

 reducible to one primitive form of matter. 



Eising in the scale of being, we find that in 

 the lowest living organisms, such as the Ehizo- 

 poda, the substance of the body itself performs 

 all the functions of life ; and on ascending to 

 the Zoophyta (as the Hydra\ they devolve almost 

 entirely upon the skin, for when the animal is 

 turned inside out, the lining of the stomach be- 

 comes the skin, and the skin becomes the lining 

 of the stomach. In the higher animals and 

 plants, different organs perform different offices ; 

 but these still retain a limited power of per- 

 forming functions which properly belong to 

 others. Thus, if the stems and leaves of plants 

 are kept from the light, they do not develop 



