314 HYPOTHESIS OF VITALITY. 



ties 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 discover 

 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 has seemed to me preferable to resort provisionally 

 to hypothesis. In order to account for the facts, I con- 

 ceive 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 temporarily its elements, and determines the precise 

 changes which shall take place when the living matter 

 again comes under the influence of certain external con- 

 ditions. 



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 bioplastic 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, which, if they 

 have not been actually designed, are at any rate admirably 

 adapted for the fulfilment of definite purposes. These 

 mechanical arrangements were anticipated, as it were, from 

 the earliest period, and their formation provided for by the 

 preparatory changes through which the structures had to 

 pass before perfect development could be attained. Can 

 these phenomena be accounted for except through the in- 

 fluence of some wonderful power or agency such as we have 



