Ill REFORMED CONCEPT OF MATTER 4I 



colloid surface is apparently a special field of force or influ- 

 ence, in which other chemical or physical reactions besides 

 selective adsorption are facilitated. The enzymes, for in- 

 stance, in the protoplasm of the cell are complex chemical 

 substances in very minute colloid form, with the surface 

 molecules or radicles specially orientated so as to facilitate 

 in a most marvellous way the chemical and physical pro- 

 cesses which are necessary for the organic activities of life. 

 But enzymes are very particular in their action, and each 

 particular process has its own particular enzyme to bring it 

 about. Thus enzymes transform the sugar or sugar-like con- 

 tents of certain plants into alcohol; but each plant has its 

 own enzyme, which will only operate on the material of that 

 plant. Similarly chlorophyll is a complex chemical compound 

 probably in colloidal dispersion in the protoplasm of leaf 

 cells and other green cells, and its colloidal surfaces are 

 '' fields " in which the energy of sunlight can synthesise the 

 carbon dioxide of the air into organic compounds which ulti- 

 mately take the form of sugar, starch and cellulose. No lab- 

 oratory has ever been able to make sunlight perform this 

 wonder; but the colloidal surface " field " of chlorophyll 

 can do it, and in that way provide for the sustenance of all 

 organic life on this globe. 



The marvellous behaviour of matter at its surfaces in the 

 colloid state, and especially its mysterious " selective " 

 power, has raised the hope that here the bridge may yet be 

 found between the inorganic and the organic. Thus Dr. S. 

 F. Armstrong says: "Enough has been said to show how the 

 conception of an orientated active structure at the surface 

 of a colloid aggregate might endow it with selective power of 

 so fine a nature as almost to merit the description of intelli- 

 gence; the further prosecution of research on these lines 

 may well serve to bridge the gap between us and the full 

 understanding of vital activity." ^ 



It has been usual to distinguish " physical " from 

 " chemical " combination. The New Physics has, however, 

 made it clear that there are two types of chemical change, 



^ Chemistry in the Twentieth Century, p. 17. 



