Extract from The Haslam Practical Guide to Dressmaking and Tailoring by G.A. & F.A. Haslam
With vintage dresses, often the original wearer would have worn a slip, which are a bit rarer these days. I imagine this is the underwear the book is referring to.
In this post-synthetic fabric age I will use something other than silk and have finally found a use for all the small ribbons that are sometimes used in shops to attach price tags or to keep sweaters on hangers, that I have been saving/hoarding as I can’t throw away something useful.