Q. I'm trying to download a chapter of the ebook "The Online Metabolic and Molecular Bases of Inherited Diseases"

After the patron sent me the link, I found a "Full Text here" button. Clicking on this, led to a page with full text. At the top of the page, there is a button "Chapter PDF". Clicking on this link, leads to a pop up page that asks to either Save or Open the pdf. I picked Save, and the pdf opened up.