THE VITAL ORDER 



scale of degrees in life as clearly as there is a scale 

 of degrees in temperature. There is an endless grada- 

 tion of sensibilities of the living cells, dependent 

 probably upon the degree of differentiation of func- 

 tion. Anaesthetics dull or suspend this irritability. 

 The more highly developed and complex the ner- 

 vous system, the higher the degree of life, till we 

 pass from mere physical life to psychic life. Science 

 might trace this difference to cell structure, but 

 what brings about the change in the character of 

 the cell, or starts the cells to building a complex 

 nervous system, is a question unanswerable to 

 science. The biologist imagines this and that about 

 the invisible or hypothetical molecular structure; 

 he assigns different functions to the atoms; some 

 are for endosmosis, others for contraction, others 

 for conduction of stimuli. Intramolecular oxygen 

 plays a part. Other names are given to the mys- 

 tery — the micellar strings of Naegeli, thebiophores 

 of Weismann, the plastidules of Haeckel; they all 

 presuppose millions of molecules peculiarly ar- 

 ranged in the protoplasm. 



On purely mechanical and chemical principles 

 Tyndall accounts for the growth from the germ of a 

 tree. The germ would be quiet, but the solar light 

 and heat disturb its dreams, break up its atomic 

 equilibrium. The germ makes an "effort" to re- 

 store it (why does it make an effort?), which effort 

 is necessarily defeated and incessantly renewed, and 



217 



