PLANT-LIFE ASSIM1LA TION. 23 



Likewise there is known to be a double 

 movement of water, ascending and descend- 

 ing. In this connection is to be noticed Trans- 

 piration, the process of throwing off water in 

 the form of vapor from the surface of the 

 Plant, especially from the leaves. Thus flow- 

 ing streams of fluid continually rise through 

 the Plant like an artesian spring, though the 

 cause of this uplift is still under discussion. 

 On the other hand water is always being taken 

 up by root and leaf. 



The Plant aliment being thus seized from 

 the outside world, cooked and distributed to 

 the organs, which obtain thereby the energy 

 for doing all this work (seizing, cooking, dis- 

 tributing), what next? Does the Plant- 

 organism continue to make the same old vital 

 round when it is once done growing? Now 

 the fact comes to light that the Plant in a 

 sense never gets done growing; as to its or- 

 ganism it is ever the unfinished and unfinish- 

 able, yearly the exogen adds a new layer to 

 its body on the outside, though it be centuries 

 old; in the endogen a similar repetition oc- 

 curs on the inside (by means Of the so-called 

 vascular bundles). So we may say that the 

 Plant is ever striving to get beyond itself, 

 seeking to reach an end by continual addi- 

 tions to itself. Thus it seems to be growing 

 an infinite series. About this growth a few 

 words. 



