Relation of Inorganic to Organic Bodies 63 



may be formed by the protoplasm, or by some ferment excreted 

 by the protoplasm, and such may be entirely absent in the other. 



Naturally the former of these methods is the most easy 

 and gradual in operation for the evolution of new species, since 

 it merely involves a very slow change in the distribution and 

 activity of centers of intra-molecular or constitutive energy. 

 The latter represents a totally new combination and distribution 

 of ether particles wdth their constitutive energy charges. 



But in this connection, were we dealing with either a simple 

 or a complex colloid mass, we know that very similar results 

 could be secured. Thus, in some of Leduc's colloid structures, 

 were the chemical action stopped at a certain stage, a simple 

 spherical body might result; were it continued so as to ensure 

 added supplies of the same substances, a branched or arbores- 

 cent body might ensue. On the other hand, were one or both 

 of the osmosizing colloids substituted for another, a structure 

 would arise that would be physico-chemically different. 



We are definitely and accurately aware, then, that the only 

 method of fundamentally altering any inorganic body as to 

 its molecular constitution is by the process of chemical sub- 

 stitution, in which by exact and predicable action and reaction 

 one or more molecules of some one compound are substituted 

 by others or may even be removed. In the inorganic kingdom 

 the total number of compounds of the elements capable of 

 being formed by natural process has been variously given at 

 from 500 to 800. In contrast to this, the organic chemist has 

 already made known about 50,000 definite compounds (26: 127) 

 as coming under his eye, and the number is constantly being 

 added to. All of the latter are either natural products that 

 are built up in plant and animal tissues, or so related by molec- 

 ular structure and decomposition change that they form part 

 of an organic whole. 



In any one series of these, such as the methane or benzene, 

 one body may differ from another only by the substitution 

 of one atom for another in each compound. But, when even 

 minute substitution change is made, it usually confers new 

 characters, new reactions, and new potentialities on each body 



