54 THE BEGINNINGS OF LIFE. 



necessity from the Persistence of Matter, which was 

 denied by none. We have seen also how firmly the 

 doctrine has gradually been gaining possession of the 

 minds of the best scientific workers of all kinds, that 

 the so-called 'vital' forces about the very name of 

 which there was formerly such a ring of mystery- 

 are, after all, nothing more than incident physical 

 forces which have been transformed and conditioned 

 by their c passage through an organism,' or, as we pre- 

 fer to express it, are physical forces which have un- 

 dergone change and have ceased to exist as such in 

 giving birth to those material combinations, which con- 

 stitute the very matter of the organism itself. As 

 Dr. Frankland has said, c An animal, however high its 

 organization, can no more generate [that is, actually 

 create] an amount of force capable of moving a grain 

 of sand, than a stone can fall upwards, or a loco- 

 motive drive a train without fuel.' The force mani- 

 fested during the contraction of muscles is the result 

 of the setting free of an equivalent amount of poten- 

 tial energy by the tissue disturbances and chemical 

 changes, of various kinds, which immediately precede 

 and accompany the motor act. And, moreover, if 

 it can be shown that the processes taking place 

 in living beings are in great part amenable to and 

 governed by ordinary physico-chemical laws, instead 

 of being processes altogether occult and peculiar j 

 if it can be shown that products hitherto believed -to 

 be producible only under the influence of vital actions 



