GENUINE - Not false; real; true
ESSENCE = 1. The quality or qualities of a thing that give it its identity 2. A extract made from a substance and retaining its basic or most desireable properties in concentrated form. b. An alcohol solution of such an extract 3. A perfume or scent.
Being an Idaho RedNeck I would define it as : A Real Stink That's my story and I'm stickn' to it.
The genuine essences were sold by druggists , listed with medicines. They could have been used for cooking or in preparing medicinal remedies. Ingredients like mint and lemon were often used in cough and cold treatments.
The bottles themselves were generic containers sold by glass houses to be used by druggists, pharmacists or grocers, who ever was putting up the product. So they are not a patent med, just a generic embossed bottle available to whoever wanted to use them, like a historical flask sort of, which was sold and then filled by whoever with whatever... As others have said they could be filled with essence of lemon, mint, what ever one wanted to sell the "essence" of...
I've seen early doyttville glass catalougs with genuine essence bottles listed as an available product...
They have always been a favorite of mine...