Now mind you, I agree with them on a lot of things, but they were tending to speak in absolutes and not back up their claims with specific research.
Of course, it's almost impossible to prove a negative and there's long been a question over what kinds of fiber were available to Civil War knitters. We know there was wool and cotton and silk, but beyond that there's been a general consensus that other fibers (angora, alpaca, mohair, etc.) were out. The thought was that one could buy alpaca fabric for example, but not alpaca yarn.
I've recently been reading an 1859 sales catalogue from Aldridge & Co., a Philadelphia dry goods store and noticed the following entry under "Hosiery":
- Children's White Cashmere Socks, and 3/4 Hose, British
- Is the fiber available to the home knitter?
- Are these machine knit?