128 ORIGIN AND NATURE OF LIFE 



plete, and to remove the completed product 

 from intermixture with incomplete stages, 

 and from the two or more unchanged reacting 

 substances. For these complex molecular 

 unions give rise to matter in a new form which 

 cannot be so easily dealt with. In many- 

 cases, when saturation is complete there are 

 found to be exact molecular relationships, 

 just as definite as those found in simple 

 inorganic mono-molecules. 



But the admission, even, of varying mole- 

 cular relationships in the multi-molecule, 

 does not preclude the reaction from being 

 truly chemical. A new territory is here 

 being investigated, and it would not be true 

 philosophy to expect details to remain the 

 same in this region as in the mono-molecular 

 one. When molecules begin to interplay, 

 instead of atoms, some modifications are 

 naturally to be expected. Also the exact 

 atomic relationships in the composition of a 

 mono-molecule, on account of the low relative 

 valencies of the atoms, can be followed with 

 great experimental exactitude. But, when 

 instead of atomic valencies rising no higher 

 than four or five, there are substituted 

 molecular valencies of thirty to sixty, then 

 the problem of following out exact relative 

 numbers of molecules of each constituent in 





