THE KERATINIZATION PROCESS 



269 



Fig. 113. Structure of medulla. Diagrams to illustrate the detailed 

 formation and structure of the medulla in hair, a, b and c are three 

 stages in the obliteration of a cell and the condensation of its contents. 

 A-G illustrates the full sequence of cell forms in which the appearance 

 and assimilation of trichohyalin (see p. 268) may be followed. Re- 

 produced from Auber (1950) by permission. The transformation of 

 trichohyalin into fibrils and its fusion with the cell membranes is indicated. 



