viii PREFACE 



ing the necessary elements. In each of these 

 changes the substance becomes more plastic, but 

 more unstable ; more nearly living, but more easily 

 decomposed. 



In the author's view of the origin of the living 

 from non-living substances the ionisation of materials 

 and formation of meres takes a great part. The 

 formation of ions is observed in many ways. It 

 occurs both in growing and disintegrating tissues. 

 It is observed in dead as well as in living substances. 

 Some of the observed facts have been noted in the 

 following pages, in which an endeavour has been 

 made to place the theory of ions before the reader, 

 and to show that ions occupy an important place in 

 biological processes. The continuous adjustment 

 of the internal relations of materials to the external 

 relations is, in the author's view of the subject, 

 brought about by the ionisation of matter, the 

 transformation of energy, and the definite com- 

 bination of these heterogeneous changes, both simul- 

 taneous and successive; and these "in correspon- 

 dence with external coexistences and consequences " 

 result in the development of the dead into the living, 

 the inorganic into the organic. 



W.T. 



NOTTINGHAM. 



