Origin of the bimodal ?melting? endotherm of ?-form crystallites in wool keratin

The melting endotherm of α-form crystallites in wool keratin appears often to be bimodal. The origin of the bimodal endotherm has been considered to correspond to the differential melting of the α-form crystallites in the domains of ortho- and para-cortical cells. An alternative interpretation is presented, in which the bimodal peak arises from the overlapping of the melting endotherm of α-form crystallites and the thermal degradation of other wool histological components.