Early Investigations on Naturally Occurring Polymers

Somewhat in advance of the widespread usage of the colloidal connotation of Ostwald and others, investigators in a number of instances seem to have favored the view that cellulose, starch, rubber, etc., are polymeric, the term being used in much the same sense as it is used today. The idea that proteins and carbohydrates are polymeric goes back at least to Hlasiwetz and Habermann, who, in 1871, considered 

Prior to the work of Eaoult, who developed (1882-1885) the cryo-scopic method for determining molecular weights of dissolved substances, and to van t Hoff s formulation (1886-1888) of the solution laws, no method was available for quantitatively determining the molecular weights of substances in solution. The vapor density method obviously could not be applied to any but very low polymers. No means was at hand for determining the state of polymerization even in instances where polymerization was suspected. 

A second factor of importance in this connection is found in the emphasis which was placed in the 1890 s and early 1900 s on secondary association of molecules. Coordination complexes, the concept of partial valences, and van der Waals forces attracted wide attention 

The levulinic aldehyde and acid obtained by Harries on hydrolyzing the ozonide of rubber demonstrated recurrence of the structure 

Later (1914) Harries agreed to a larger ring of five, and eventually of seven, isoprene units. 

---