440 THE CAUSES OF THE 



XI 



destroyed as are born ; that is the inevitable ulti- 

 mate result of the rate of production. Now, what 

 is the result of all this ? I have said that there 

 are forty-nine struggling against every one ; and 

 it amounts to this, that the smallest possible start 

 given to any one seed may give it an advantage 

 which will enable it to get ahead of all the others ; 

 anything that will enable any one of these seeds to 

 germinate six hours before any of the others will, 

 other things being alike, enable it to choke them 

 out altogether. I have shown you that there is 

 no particular in which plants will not vary from 

 each other ; it is quite possible that one of our 

 imaginary plants may vary in such a character as 

 the thickness of the integument of its seeds ; it 

 might happen that one of the plants might pro- 

 duce seeds having a thinner integument, and that 

 would enable the seeds of that plant to germinate 

 a little quicker than those of any of the others, and 

 those seeds would most inevitably extinguish the 

 forty-nine times as many that were struggling 

 with them. 



I have put it in this way, but you see the practi- 

 cal result of the process is the same as if some 

 person had nurtured the one and destroyed the 

 other seeds. It does not matter how the variation 

 is produced, so long as it is once allowed to occur. 

 The variation in the plant once fairly started tends 

 to become hereditary and reproduce itself; the 

 seeds would spread themselves in the same way 



