From Inorganic Matter to Life. 159 



To trace the course of this change, Mr. Spencer 

 goes back to the invisible world of atoms. He sup- 

 poses them aggregated into molecules, and these into 

 other aggregates, and so onward, in ever more com- 

 plicated systems, until we reach the molecule of 

 which protein is formed. We have then found a 

 form of matter modifiable with extreme facility by 

 surrounding agents. This protein " is capable of ex- 

 isting under probably at least a thousand isomeric 

 forms ; and, as we shall presently see, it is capable 

 of forming with itself and other elements, sub- 

 stances yet more intricate in composition, that 

 are practically infinite in their varieties of kind. 

 Exposed to those innumerable modifications of con- 

 ditions which the earth's surface afforded, .... 

 this extremely changeable substance must have 

 undergone now one now another of its countless 

 metamorphoses. And to the mutual influences of its 

 metamorphic forms, under favouring conditions, we 

 may ascribe the production of the still more compo- 

 site, still more sensitive, still more variously-change- 

 able portions of organic matter, which, in masses more 

 minute and simple than existing Protozoa, displayed 

 activities varying little by little into those called 

 vital actions which protein itself exhibits in a certain 

 degree, and which the lowest known living things 

 -exhibit only in a greater degree." * 



Biology, Vol. J., Appendix, p. 483. 



