104 PHILOSOPHICAL NOTES ON 



be the main organs of suction, and the fluids would have to ha 

 forced to the extremities of the branches and leaves. Hence 

 there would be the beginning of the elaborate fibro-vascular system 

 of the higher plants. It would develop pari passu with an 

 elaborate root system. An epidermis also would have become a 

 necessity, to protect the softer parts from the inclemencies of the 

 air. 



In this way we may form some conception of the emergence 

 of seaweeds from water into the air, disseminating themselves in 

 myriads of modified forms, in countless ages, over the land, their 

 different parts becoming modified to suit new and very distinct 

 surroundings. Myriads of experiments, of course, must have 

 occurred, and myriads of failures must have been gone through, 

 until some modification, more suited than others to the conditions 

 which beset it, could live. 



What one has to do is to allow unlimited time, and an 

 unlimited number of variations, in order that vegetable organisms 

 might very gradually become adapted to new surroundings. 



Evolution, as I said, does not always mean a forward progres- 

 sion of any organ once formed. It sometimes means just the 

 reverse. A striking instance of this is the evolution of our 

 modern horse. Starting with five digits, he was modified into an 

 animal with three digits, and eventually became the modern horse, 

 with only one digit.* 



We notice evolution in a similar retrogressive way in many 

 other plants. Plants with five stamens lose one, two, three, or 

 four stamens, and are transformed into one-stamened plants; 

 others, with petals, become apetalous; leafy plants become 

 aphyllous. 



Important organs in one set of plants are traced to mere teeth, 

 or bristles, or hairs in others. While minute, insignificant organs 

 in one set become enlarged and important organs in others. 



Plants seem to have various ways of adapting themselves to 

 new conditions. Now they retract one organ and protrude 

 another, much as if they were sensitive organs, governed by some 

 central supervising and adaptation-discovering ganglion. 



* The orchid must have started with three or six stamens, but now many 

 have only one. The pea is supposed to have started with many carpels, 

 but now has only one. 



