646 THE POPULAR SCIENCE MONTHLY. 



that a nerve is, in its essence, nothing hut a linear tract of specially 

 modified protoplasm between two points of an organism one of 

 which is able to afiect the other by means of the communication so 

 established. Hence it is conceivable that even the simplest living 

 being may possess a nervous system. And the question whether 

 plants are provided with a nervous system or not thus acquires a new 

 aspect, and presents the histologist and physiologist with a problem 

 of extreme difficulty, which must be attacked from a new point of 

 view and by the aid of methods which have yet to be invented. 



Thus it must be admitted that plants may be contractile and loco- 

 motive ; that, while locomotive, their movements may have as much 

 appearance of spontaneity as those of the lowest animals; and that 

 many exhibit actions comparable to those which are brought about 

 by the agency of a nervous system in animals. And it miist be 

 allowed to be possible that further research may reveal the existence 

 of something comparable to a nervous system in plants. So that I 

 know not where we can hope to find any absolute distinction 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 certainly hold good for 

 the vast majority of animals and j^lants, 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 projDortion ; with 

 atmospheric air containing its ordinary minute dose of carbonic acid ; 

 and with nothing else but sunlight and heat. Under these circum- 

 stances, 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 

 crops of beans, just as if it were grown in the garden or in the field. 



The weight of the nitrogenous proteine compounds 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, am- 

 monia, potash, lime, iron, and the like, in combination with phosphoric, 

 sulphuric, and other acids. Neither proteine, nor fat, nor starch, nor 

 sugar, nor any substance in the slightest degree resembling them, 

 has formed part of the food of the bean. But the weights of the car- 

 bon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, and other ele- 

 mentary bodies contained in the bean-plant, and in the seeds which it 

 produces, are exactly equivalent to the weights of the same elements 

 w^hich have disappeared from the materials supplied to the bean dur- 

 ing its growth. Whence it follows that the bean has taken in only 

 the raw materials of its fabric and has manufactured them into bean- 

 stuffs. 



