20 STRUCTURE AND FUNCTIONS 



noticed, that one condition essential to that part 

 of their structure is darkness; and now it is 

 found that light is equally necessary for the 

 stem and leaves and other green parts of the 

 plant. If proof were wanting to convince us 

 of the almighty mind of the Being who has so 

 wisely constituted this world, it might be found 

 in the simple yet perfect arrangement now 

 under consideration. It is a proof of the most 

 perfect adaptation of the plant, to the condi- 

 tions and circumstances necessary for its 

 growth. 



We now come to speak of the seed or fruit 

 of plants. The object to which all the other 

 functions of the plant are subordinate, or to 

 which at least all parts have reference, and one 

 which in its importance to mankind cannot be 

 too highly appreciated. 



Seeds vary in size, colour, shape, &c. to such 

 an infinite extent as to be scarcely within the 

 scope of human understanding; but all of them 

 possess one uniform arrangement for the protec- 

 tion of the germ from injury, and it will be im- 

 portant to consider what this general arrange- 

 ment is, and also the changes that the seed 

 undergoes in the process of germinating. 

 ' All seeds consist of a farinaceous pulpy mat- 

 ter, covered on all sides by two or three mem- 

 branes which serve to protect the seed from 

 any casual injury. The pulpy matter contains 

 at one end, the heart, or as it is more correctly 

 termed the germ or embryo plant, and in all 

 cases it must be remarked that the pulpy fari- 

 naceous matter is the proper food of the nas- 



