In a primeval sea, life probably originated from further development of giant molecules in solution. How these were formed we do not know--as a possible cause we might assume some chance combination of amino acids. In the solid state well-defined, closed molecules are rare and we are, therefore, led to believe that such entities as protein molecules were first built up in a solution. At present we find them only as synthesis products in living beings. The viruses occupy an intermediate position between dead and living matter, between protein molecules and bacteria and they are known to exist in a liquid or semisolid state.
Such giant molecules as we know from the solid, crystalline state and which are incapable of directly going into solution without the action of chemical agents are not so well-defined. They mostly represent the repetition of a basic unit in various degrees of polymerization.
It was through physico-chemical studies of protein solutions that the existence of well-defined giant molecules was found. The colloid character of proteins was recognized at an early date--as a matterof fact the term "colloid" was coined from observations on a protein, gelatin--but the monodispersity or paucidispersity of these substances could not be proved by meansof the methods in use at that time.
Convection-free sedimentation in the ultracentrifuge combined with refined diffusion measurements gave the surprising result that most of the proteins in solution and some of those in the condensed state were built up of well-defined molecular units. An enthusiastic team of young research men--rather international in character---carried out the first observations of this kind in Upsala (the American Nichols, the Austra-* Talk presented at the Medal Day Meeting at The Franklin Institute, October 19, 1949. (Read by Dr. 7. Burton Nichols, in the absence of the attthor.