Gilbert Bros & Co of Baltimore put out several products, a few in embossed flasks and a couple of rectangular medicine types.....The Yager's is a new one on me as I don't think they had anything to do with Yager's Sarsaparilla....could be wrong, as Baltimore is not my "territory."
More info, Yagers Sarsaparilla
Product of Gilbert Bros. & Co. Balimore MD. The firm was located at 9-13 Howard from 1896 to 1900 at 308 W Lombard in 1912 and 308-310 W Lombard from 1913-1930
Amber 8 1/2" x 3" x 2"