Thus, one examines the structure of the polymer indirectly through a chemical reaction. A reaction that acts specifically at the 1,2-glycol linkages to cleave a polymer breaks it into smaller units, the size of which is determined by the number of monomer units between these sites. Treatment with periodate can cause this cleavage. On the assumption that all 1,2-glycol linkages are cleaved and that none of the head-to-tail linkages are cleaved during treatment with periodate, ∆ is equal to the increase in the number of molecules after cleavage divided by the total number of monomer units, as in equation (5.14):