8o PRESENT-DAY RATIONALISM 



Nature." We see everywhere not only exquisite order and 

 arrangement in the structure of plants and animals, but a 

 unity of plan pervading the whole. We see, in endless com- 

 plexity, beauty and simplicity, the most perfect adaptation 

 of means to ends. The advocates of the physical theory 

 are at least bound to show how it is probable that this 

 exquisite arrangement and unity of plan could have been 

 produced by means of chemical and physical agencies. 



Mr, Croll here instances the formation of a leaf of a 

 tree, but as Prof. Dolbear referred to the reserve-food 

 material in the grain of corn, I will take that as an 

 illustration of Determination and Directivity, 



The odj'ect of the grain is, of course, reproduction. 

 Having this, so to say, in view, Nature secures the im- 

 pregnation of the female germ-cell by the male sperm- 

 cell contained in a separate organ, the pollen grain. 



There are two fertilising bodies in this latter, so that 

 when the origin of the new plant or embryo is thus 

 secured, the other "fertiliser" pays attention to another 

 body in the same chamber or embryo sac. This latter 

 having been, so to say, impregnated, undertakes to make 

 the reserve-food material for the embryo. Both proceed 

 to grow and develop independently of each other ; so that 

 when the grain is ripe the embryo lies freely at one end 

 of the grain with the "endosperm," as it is now called, at 

 the back of it. 



The endosperm consists of a great number of chambers 

 called cells in which the food is stored up ; but how came 

 it there ? The main ingredient consists of starch grains. 

 This was piade in the leaves, but being solid was changed 

 into .soluble sugar, conveyed away by proper tubes, etc, 

 to the growing grain, where the sugar is re-formed into 

 starch in view of the resting period the grain goes through 

 before it germinates in the following year. Besides starch 



