Disorder is characteristic of nerve myelin.

An X-ray diffraction pattern from the myelin in frog sciatic nerve has been obtained using the intense synchrotron radiation from the storage ring, SPEAR. Data with good statistical accuracy are obtained in a few minutes by using a scintillation counter or position-sensitive detector. The same indications for stacking disorder are seen as in previous conventional exposures which required one to two days. Thus, the stacking disorder is characteristic of myelin in a freshly dissected nerve. The present data, obtained with a more nearly monochromatic X-ray beam than in the previous study, remove one of two ambiguities which bear on the possible phasing of the higher order Bragg reflections.