VI ANIMALS AND PLANTS 173 



between animals and plants, unless we return to 

 their mode of nutrition, and inquire whether 

 certain differences of a more occult character than 

 those imagined to exist by Cuvier, and which cer- 

 tainly hold good for the vast majority of animals 

 and plants, are of universal application. 



A bean may be supplied with water in which 

 salts of ammonia and certain other mineral salts 

 are dissolved in due proportion ; with atmospheric 

 air containing its ordinary minute dose of carbonic 

 acid ; and with nothing else but sunlight and heat. 

 Under these circumstances, unnatural as they are, 

 with proper management, the bean will thrust 

 forth its radicle and its plumule ; the former will 

 grow down into roots, the latter grow up into 

 the stem and leaves of a vigorous bean-plant ; and 

 this plant will, in due time, flower and produce its 

 crop of beans, just as if it were grown in the 

 garden or in the field. 



The weight of the nitrogenous protein com- 

 pounds, of the oily, starchy, saccharine and woody 

 substances contained in the full-grown plant and its 

 seeds, will be vastly greater than the weight of the 

 same substances contained in the bean from which it 

 sprang. But nothing has been supplied to the bean 

 save water, carbonic acid, ammonia, potash, lime, 

 iron, and the like, in combination with phosphoric, 

 sulphuric, and other acids. Neither protein, nor 

 fat, nor starch, nor sugar, nor any substance in the 

 slightest degree resembling them, has formed part 



