error in chapter 2

Lucky for me I have a couple of people reading the story. I'm very grateful to dorjejaguar for noticing that brewer's yeast might not contain any vitamin B12 after all. I've added a note in red text at that point in the story (a little more than halfway through chapter 2) til I work out a way to alter the story so that it works.

Thanks again dorjejaguar for coming to my rescue.