216 



KERATIN AND KERATINIZATION 



Fig. 93. Progressive dispersion of the unconsolidated pre-keratin by 

 saturated urea. Above D the partly-hardened protein swells only and to 

 a diminishing degree as the hardening progresses. Birefringent cortex 

 shown black. The time taken for the whole action is from 5 to 10 min 

 (from Mercer, 1949d). 



2000/X 



Fig. 94. Swelling (percentage of original area on ordinate) of a follicle in 



a, water, b, saturated urea as a function of the distance from the base of 



the papilla (Mercer, 1949b). 



