THE PLANT AND ITS FOOD. ij 



the action of root-hairs as tubes with open pores 

 at their tips. But the gravest misapprehensions 

 current among us are due to the crude ideas as to 

 what a plant really is : this, I take it, is owing to 

 the difficulty of grasping what physiologists mean 

 by organised structure, and leads to regarding the 

 living being either as a mere aggregation of 

 chemical compounds, built up by the ordinary 

 play of chemical forces, as we know them, acting 

 on dead matter, or, as in the days before organic 

 chemistry, as a mysterious entity endowed with 

 " vital force," and with properties not amenable to 

 scientific investigation. The mistaken notions as 

 to the powers of roots to " select " those sub- 

 stances which the plant requires, and to reject 

 useless ones was merely an expression of this 

 belief 



The rock on which all are liable to come to 

 grief the chemist or physicist who requires all 

 his facts in terms of analyses and proportions by 

 weight, and therefore takes too mechanical a view 

 of the subject, or the man who is not scientifically 

 trained at all, and therefore is more liable to go 

 to the other extreme and regard the plant as a 

 mysterious something which grows and has 

 poetical associations and traditions is the great 

 fact of organised structure, and it is the recogni- 

 tion of this fact and some of its consequences 

 which has altered the whole position of the 

 subject, and brought the study of the plant into 

 the domain of physiology. The living plant, its 

 structure and organisation, the functions of its 



