Last time I mentioned this one, I remember getting told by a chemist that the type of arsenic compound, although present in large amounts, was not one of the very high toxicity ones.
I gather the paris green reacts with dampness to form arsene gas, so its when yove got both paris green and damp that you get exposure.
Paris green is a distinct colour, but since it can be used in different strengths it covers a range. When I found some I had it tested. Its not expensive.
Paris green was fashionable in the 1890s IIRC. And no, I dont mean I was there at the time <IMG SRC="http://www.periodproperty.co.uk/discussing/smileys/smile.gif" BORDER=0 ALT="">
You can get a very rough idea of when paint went on by looking at the layers, seeing where it sits, near surface, half way, or near the wood/wall/etc.
They sure were funny with their colours. I guess if you've lived all your life with a small set of dull colours, in relatively cramped houses with small windows, a bit of OTT was real refreshing.
The National Trust does have some more basic dwellings - when I have time I'll dig out a few, Hill Top and Townend in Cumbria are wonderful - Yoemen's rather than peasant's houses i admit, but super stuff.
Beamish Museum, Ryedale Folk Museum - a number of other places around which have reconstructions of simple dwellings from the past and are worth a visit.