Protoplasm 189 



from the cold of space to which they are 

 exposed, for maintaining them at a tempera- 

 ture appropriate to organic existence, and 

 likewise for supplying and generating the 

 energy for their myriad activities. It has 

 become in fact a central sun, and source of 

 heat, solely because of its enormous size 

 combined with the fact of the mutual 

 gravitative attraction of its own constituent 

 particles. No body of moderate size could 

 perform this function, nor act as a perennial 

 furnace to the rest. 



Application to Protoplasm. 



Very well then, return now to our com- 

 plex molecular aggregate, and ask what new 

 property, beyond the province of ordinary 

 chemistry and physics, is to be expected of 

 a compound which contains millions or 

 billions of atoms attached to each other in 

 no rigid, stable, frigid manner, but by loose 

 unstable links, enabling them constantly to 

 re-arrange themselves and to be the theatre 



