There are countless cases in which e x a c t a n a l y s i s along classical lines is extremely fruitful, giving results otherwise not obtainable. It here not concerns the chemical, but the "zoological" sector. Because the protein structures are hereditary and with it indicate phylogenetic kinship, a chemical detection of phylogenetic kinship is possible. An example : comparative stereochemical specifity of liver-esterase in species and genera of the hominid families (apes and humans).