CHAPTER II. 



HISTORY OF THE THEORY OF THE NUTRITION OF PLANTS. 



1583-1860. 



THAT plants take up certain substances from their environ- 

 ment for the purpose of building up their own structures 

 could not be a matter of doubt even in the earliest times ; it 

 was also obvious, that movements of the nutrient material must 

 be connected with this proceeding. But it was not so easy to 

 say, what was the nature of this food of plants, in what manner 

 it finds its way into and is distributed in them, and what are 

 the forces employed ; it was even for a long time undecided, 

 whether the food taken up from without suffers any change 

 inside the plant, before it is applied to purposes of growth. 

 Such were the questions which had engaged the attention of 

 Aristotle, and which formed the chief subject of Cesalpino's 

 physiological meditations. 



But the questions respecting the nutrition of plants acquired 

 a much more definite shape in the latter half of the iyth 

 century, when the various phenomena of vegetation began to 

 be more closely observed, and some attempt was made to 

 understand their relations to the outer world. Malpighi, the 

 founder of phytotomy, was the first who undertook to explain 

 the share which belongs to the different organs of the plant in 

 the whole work of nutrition ; guided by analogy, he perceived 

 that the green leaves are the organs which prepare the food, 

 and that the material so prepared by them passes into all parts 

 of the plant, there to be stored up or employed for purposes 



