Does the cap unscrew ? There are always exceptions to the rule, I have seen many screw top bottles (mostly pill), and several smelling salts that have screw tops from the 1800's. The threads are usually kind of crude, and the top is usually ground. Bottle could be a nasal douche or inhalant type, the idea of morphine is iffy but not out of the question. The cap is shaped in such a way that it probably had a hose or small nipple on the end. Is it embossed anywhere ? I have seen lots of bottles, I don't remember seeing too many of those, although I have seen some cobalt blue bottles similar in shape. Hope this helped.