MOLECULAR AND M ACROMOLECUL AR STRUCTURE 



167 



larger-scale structures have not reformed. On the other hand, experimental 

 procedures, such as the " heat-moisture treatment " of Bear and Rugo 

 (1951), also exist by which the small-scale molecular order may be de- 

 ranged while leaving the macromolecular pattern largely intact. 



The long spacings revealed by diffraction (30-700 A) overlap those 

 which can be resolved in the electron microscope (50 A and longer) and in 

 some instances the two methods give results in good agreement. For 



Table 9. 



Small-Angle Diffractions of oc-Keratin Fibres! 

 Meridional and near meridional reflections. 



Equatorial reflections 



The d columns contain the measured spacings which, when 

 multiplied by the assigned k or h indices, yield the large fibril 

 period, b , or the large transverse fundamental spacing, a , of 

 80-90 A. The / columns indicate in rough fashion the relative 

 intensities of the diffractions. 

 * Overlaid with faint, poorly-oriented rings, probably due to 



lipid. 

 t From Bear and Rugo (1951) 



