INTRODUCTORY. 25 



be imitated artificially, or satisfactorily explained. It 

 takes up non-living matter in solution and communi- 

 cates its wonderful properties to it. Having increased 

 to a certain size, the mass of living matter divides 

 into smaller portions, every one of which possesses 

 the same properties as the parent mass, and in equal 

 degree." 



" Scientific investigators have hitherto failed to dis- 

 cover any laws by which these facts may be accounted 

 for. But rather than ignore or misrepresent them, or 

 affirm anything concerning them which we cannot 

 prove, as some have done, it seems to me preferable 

 to resort provisionally to hypothesis. In order to 

 account for the facts, I conceive that some directing 

 agency, of a kind peculiar to the living world, exists in 

 association with every particle of living matter, which, 

 in some hitherto unexplained manner, affects tempo- 

 rarily its elements, and determines the precise changes 

 which are to take place when the living matter again 

 comes under the influence of certain external condi- 

 tions." In higher animals, besides giving rise to the 

 phenomena above referred to, every instant during life 

 in every part of the organism, this supposed agency 

 or power, acting under certain circumstances at an 

 early period of development, so disposes the material 

 which it governs, that mechanisms result of most 

 wonderful structure, admirably adapted, as they have 

 been evidently actually designed, for the fulfilment of 



