2QO THE LIFE OF THE PLANT 



these general laws ultimately be if, starting with them, 

 we arrive as a necessary conclusion at the startling 

 perfection of the organic world ? We shall devote this 

 our last chapter to answering this question. 



Hitherto, whenever we have undertaken to explain 

 particular phenomena of vegetable life, we have always 

 tried to explain them by more general and compre- 

 hensive physical and chemical laws. In the majority 

 of cases we have succeeded more or less fully, without 

 even once having had recourse to the mysterious vital 

 force of which such lavish application was made by 

 earlier physiologists. We have not proved the inade- 

 quacy of this said vital force with its indefinite attri- 

 butes and intangible sphere of action ; we have not 

 even ventured to refute its very existence ; we have 

 simply not found room for it in our lectures and we 

 have never had cause to regret it. 



But now the question arises : Can this method of 

 explanation be applied to all the facts of vegetable life ? 

 Are we able, for instance, to explain by means of 

 physical forces alone the origin of the remarkable and 

 perfectly adapted forms which we studied especially 

 in our last two chapters ? Can we, for instance, by any 

 possible combination of physical forces at work at the 

 present moment, explain the formation of the flower of 

 the sage plant, so wonderfully adapted in all its details 

 to the co-operation of insects in the process of cross- 

 fertilisation so beneficial to the plant ? Or can we 

 by the same means explain why the leaves of the 

 catchfly or the sundew possess all the necessary 

 mechanical and chemical properties for making them 

 perfect implements for catching and devouring insects ? 

 Apparently not. Evidently all these forms, or rather 

 their expediency, cannot in the least be accounted for 

 as a necessary outcome of the interaction of the sub- 

 stances and forces under the influence of which the 

 organism investigated has been formed. But if we 



