I forgot to mention this...
The ideology of rejecting the use of blood transfusions was also, at the time, reflected in the WT's alliances with the world of chiropractry and oesteopaths. 'Bloodless surgery' at the time of WW2, was a term used by chiros - a form of 'deep massage' that was practiced by - guess who? - Dr. Felix Kersten, Heinrich Himmler's doctor. Kersten was the 'hero' of the JWs during the war. There is much more I could say about how the WT's quasi-medical beliefs were the basis for implementing a full-on blood prohibition and the JWs relationship with Himmler.
When I started to examine the history of the bloodless world, there was very little on the internet to fill in what I wanted to know - where did bloodless surgery originate and how come the JWs couldn't have blood? What was the connection and was there one? So most of my early research was done with the aid of much 'hard research' - I buried my nose in hard copy. Everything from a copy of Dr. Felix Kersten's journal to loads of stuff on Heinrich Himmler, the German who was treated by a 'bloodless surgeon', the friend of the JWs. I even frequented the medical library at the university hospital, looking for where and when bloodless medicine came about. I found lots, but it was hard.
It wasn't until a few years later that the current 'history of bloodless medicine' became available online. And...guess what? One of the authors of a textbook that is used in educating blood management professionals is written by a JW doctor. From Germany. With their version of 'the history of bloodless medicine'. You now can find out where it came from and all that...from a Jehovah's Witness. Watchtower propaganda.
Funny how that went full circle.