but chemical powers, and all the physical actualities of the body 

 must exist as chemical possibilities in its germ. The germ must 

 represent, not physically but chemically, the fully developed 



If such be the case the molecules of the germ must be adapted 

 to develop, by chemical assimilation, not only into every tissue of 

 the body, but into every special portion of every tissue. Every 

 region must be potentially present in the germ, each molecule of 

 which must have its special polarities, and be adapted to a special 

 mode of development. 



Molecules are not produced by a " fortuitous concourse of 

 atoms." Complex molecules are built up by successive steps of 

 synthesis, and the mode of arrangement of the atoms is more im- 

 portant than their numbers and kinds. Even slight changes in 

 this particular may cause marked changes in the physical charac- 

 ter of the molecule. 



The energies of the molecule are solely those of affinity. Two 

 molecules of different formation differ in their chemical polarities, 

 and their relations with exterior matter depend strictly upon the 

 character of these polarities. Oxygen and hydrogen atoms unite 

 to form a polar molecule of water. A number of water molecules 

 combine with carbon to form a polar molecule of starch or sugar. 

 This may in some way combine with ammonia to form a nitro- 

 genized molecule. And so, perhaps by many steps of synthesis, 

 the most complex molecule is finally attained. But in the forma- 

 tion of the final and of every intermediate molecule, an undevia- 

 ting chemical principle must be obeyed. Each must be com- 

 posed of acid and basic, or positive and negative constituents, and 

 thus be a chemically polar organism. Thus it will be polar not 

 only as a final compound, but each of its constituent molecules, 

 down to the lowest of all, will also be a polar compound. And 

 each minor polarity in the mass will retain its special character 

 intact, and must manifest its peculiar affinities should it be set 

 free by disintegration. 



Instead of considering the polarities of constituent molecules, 

 we may approach the subject from another direction. An organic 





molecules, 



aggregated primarily into cells, and secondarily into various y 

 divergent tissues. The physical characters of these tissues de- 

 pend on the chemical affinities and polarities of the cells com- 



