I agree to that and am sorry you take the question of reference as an attack on your collection. Not intended and not necessary.
We have plenty of reference of cupping jars; these feature in many general glass catalogues such as Meisenthal and Holmegaard all through the 19th century. Cupping jars come in many shapes and forms, and had many uses in the world of pharmacy and doctoring. There were industries (Oullins in Lyon for instance) producing these simple forms for third parties: pharmaceutical wholesellers, doctor's outfitters etc. As ventouses are hardly ever marked, proving a manufacture is mostly impossible.
Leech
jars come in many forms, both pottery and glass. The essence is these are tall, footed, have a ball shaped bowl to foil any escape attempt and have a flat rim.
As for transport, leeches were transported in lidded pewter containers as per
http://www.sangsue.ch/Dateien/sangsue_ordre_pharmacien.pdf which also gives some wriggly statistics.
And as for applicators, these were various glass items with a narrow neck allowing the precise positioning of the suckers. Ventouses were used with a piece of cardboard with holes in it. Three leeches in a ventouse were applied, a few drops of wine would entice them to flee to the cardboard with the exposed skin and yum yum bite the host. The ventouse would then be taken away. For single application a glass tube would be used.
Nowhere in the story, and nowhere in the medical catalogues can flanged "leech pots" be found. There are pots much like it for packaging anchovies, for various preserves or for dry good storage. But none mention leeches specifically.
There we have the dilemma. And that is why we would like to see some reference that these are specifically for leeches. Their similarity in shape to leech
jars is inconclusive.
curious as ever.
Ivo