Myelin is a fatty/proteinaceous substance that insulates axons. The myelin sheath is produced by two kinds of cells but is not cellular in itself. I don't particularly care whether you like me or not. What I do care about is people (and you are by no means alone) who take it on themselves to peddle misinformation on this website about matters touching on the medical. Your confusion about the nature of the myelin sheath is harmless. Your pontifications about vitamin supplements, among other medical issues, may not be, and what I pick up from your own posts about your own medical issues suggests that you are not exactly the best person to be proffering medical advice here. Actually, another website that promotes Irish music had a strict policy at one time that forbade unqualified persons from posting medical "advice." I had many differences with that website's owners, but that was a good policy that we could well adopt here. I would remind you that Joe Offer fired across your bows very recently about your serial habit of peddling misinformation. Joe and I frequently cross swords here, but on that occasion he was absolutely spot on. And perhaps Maggie will note that this is a direct response to a matter raised in this thread and to the fact that my name was used in the post above this one. And that I'm being polite, measured and uncondescending.