This is an antique, cork topped Dr. W (YY) B. Caldwell medicine bottle embossed with the brand name and "Monticello, Illinois". The number "5" is embossed on the bottom. The vintage quack remedy bottle likely dates between the late 1890s and 1930s. Note what appears to be the letters YY are actually a fancy "W". My father, an avid bottle digger, discovered the bottle over 40 years ago in the ruins of an old southern plantation home in Virginia. The bottle is in nice condition, free of breaks with the exception of a crack along the side bottom that does not appear to go all the way through the glass. (See photos). The bottle is a nice light green to aqua hue with good clarity for a dug bottle with some light soil or mineral deposit. The bottle measures about 9.25" x 2.75" x 1.75".
William Burr Caldwell remedies were a popular seller from the 1880s up into the mid century 1900s. Embossed variants range in age from 1895 until 1962. Perhaps Caldwell's most popular product was his Syrup of Peptin, an antiseptic and peptonizing agent. Dr. Caldwell created the remedy initially as a means to treat diphtheria but it was primarily used to treat constipation and an assortment of other ailments.