356 THE WORLD OY LIFE 



I find, however, that Professor Anton Kemer, in his great 

 ■work on The Natural History of Plants, fully recognises this 

 great fundamental problem, and even recurs to the much 

 derided " vital force '' as the only help to a solution of it. 

 He says: 



" The phenomena observed in living protoplasm, as it grows and 

 takes definite form, cannot in their entirety be explained by the 

 assumption of a specific constitution of protoplasm for every dis- 

 tinct kind of plant, though this hypothesis may prove useful when 

 we enquire into the origin of new species." 



Again he says: 



" In former times a special force was adduced, the force of life. 

 More recently, when many phenomena of plant-life had been suc- 

 cessfully reduced to simple chemical and mechanical processes, this 

 vital force was derided and effaced from the list of natural 

 agencies. But by what name shall we now designate that force in 

 nature which is liable to perish whilst the protoplasm suffers no 

 physical alteration and in the absence of any extrinsic cause; and 

 which yet, so long as it is not extinct, causes the protoplasm to move, 

 to enclose itself, to assimilate certain kinds of fresh matter coming 

 within the sphere of its activity and to reject others, and which 

 when in full action makes the protoplasm adapt its movements un- 

 der external stimulation to existing conditions in the manner which 

 is most expedient? 



" This force in nature is not electricity nor magnetism ; it is not 

 identical with any other natural force; for it manifests a series of 

 characteristic effects which differ from all other forms of energ}\ 

 Therefore, I do not hesitate again to designate as ' vital force ' this 

 natural agency, not to be identified with any other, whose immedi- 

 ate instrument is the protoplasm, and whose peculiar effects we call 

 life. The atoms and molecules of protoplasm only fulfil the func- 

 tions which constitute life so long as they are swayed by this vital 

 force. If its dominion ceases they yield to the operation of other 

 forces. The recognition of a special natural force of this kind is 

 not inconsistent with the fact that living bodies may at the same 

 time be subject to other natural forces" (p. 52). 



