Isolation and Characterization of Myelin

In the second edition of the book Neurochemistry, Rossiter (1962) stated, “Since pure ‘myelin’ is not available for direct chemical analysis, the neurochemist has been compelled to deduce the constituents of myelin from such analyses as are practicable.” The available analyses were extensive. Qualitative information had been accumulating from histological staining techniques since the latter half of the nineteenth century. Quantitative studies on brain constituents from which information on myelin could be deduced began shortly after the turn of the century. Thus in his chapter on “The Myelin Sheath, Metabolism of Myelin and Experimental Demyelination,” Rossiter was able to discuss myelin composition and metabolism with considerable assurance and accuracy. The direct analysis of myelin constituents was, however, not possible until techniques were developed for isolating myelin membranes essentially free of other subcellular structures. The first of such procedures were being developed and published in the same year Neurochemistry was published. In this chapter, I will discuss isolation procedures and the composition of purified myelin obtained by these procedures.