Tom,
did a bit of searching and came up empty.
Did notice that it is a screw type meaning it is not real, real old.
Most old ones were blue, but had no writing on them, they did have some on bottom like yours.
Tablets came after the original liquid.
Suggest you post it on
http://www.antique-bottles.net/forum/
they are good on digging up info.
I think it still comes in a blue bottle since it is bad looking stuff in a clear bottle.
I was wrong on the above, it is now in a blue plastic.
Yours say "Tablets", they are now called "Caplets.
If I had to take a guess I would say after 1960. I could be way off on that.
Yours is an attractive looking bottle.
Sorry I could not help more.
have a good un.............
SHERMANVILLE ILLINOIS