Plate 13 



Cross-section of the cortex of a human hair in the keratinizing zone 

 of the follicle to show the arrangement of fibrils. N, nucleus ; M (arrows), 

 cell membranes bounding the cortical cells; p, pigment granules; P, 

 particulate cytoplasmic residue. Higher magnifications of fibrillar 

 keratin appear in Plates 14A, 15 and 16. 



