||P.S106 right column 2nd paragraph: "The cortex: This morphologically dominant component of hair is made up of elongated, interdigitated, spindle-like cells approximately 100 μm long and 5 μm across at the maximum width. The cells are fused tightly and oriented parallel to the axis of the fiber. Each cell is packed with fine, axially oriented filaments (microfibrils) that consist of highly organized helical proteins responsible for the diagnostic x-ray diffraction pattern of α keratins. The microfibrils are approximately 7 nm in diameter and are grouped into larger units called macrofibrils. By using specific staining techniques of electron microscopy, the structural resolution of these fibrillar assemblies has been accomplished. The results indicate that each macrofibril represents a structural composite consisting of rods of microfibrils embedded in cystine-rich matrix (Fig 5)."