I just got ahold of a 1953 (7th) Edition on this book. One section details how to test for voltage using Fingers and Tongue.
I wonder how long that section stayed in the Book?
When my wife and I bought our first house, and before I got into the trade, we had an electrician come over to move a ceiling outlet for a light fixture. He was a former school teacher and friend of my father-in-law. I watched him as he worked and offered any assistance. At some point he checked to see if the circuit was live and did exactly that - used two fingers! Never forgot that. Years later when I was apprenticing I told my journeyman this story and despite being in the trade for nearly 40 years he said he never seen anyone in the trade do that.
In Austria I've seen panels partly made of wood well into the 1970s. My parents own a weekend home that received a new combo meter enclosure/consumer unit in 1976. The visible parts are all powder-coated metal but once you get behind the covers and frame it's a wooden box lined with asbestos. I suspect that might have been an ad-hoc solution on site because the wall is only barely thick enough to accommodate the unit, more commonly these enclosures were just open and you could see the plastered brick wall through them. I think completely enclosed meter cabinets only became a requirement in the mid-1990s so now there's usually a metal tub. Mind you, these things are large, most distribution network operators suggest three-meter enclosures for single-family domestic buildings, either for a night-rate meter and tariff switch or more recently for photovoltaic cells with a dedicated meter.