It doesn't appear that this shape is confined solely to the mid C19 - according to Andy McConnell's book he gives a date range of 1800 to 1870 for these things................ and some additional information from his indispensable book .........
Called flasks or flagons (from the French
flacon), typically they have oval-sectioned bodies, short necks, and neck mounted finger-rings (although not all have this last feature). Made in a variety of colours plus clear and apart from undecorated examples like this one, they are seen in uranium, some with gilt decoration and some with engraving.
Apparently, based on an earlier C18 shape called
Bocksbeutel - literally a goatbag - hence I suppose the squashed shape.
Said book shows an example very similar to this one - even down to being the same height and colour, for which the date is given as c. 1840, and showing the nipple-domed stopper - so spot on for Ivo.
