1. Cupping jars and Leech jars are popular collectables that seem to have become defined by the collecting world in a particular manner based solely on shape.2. There appears to be no recent and definitive research in the subject.3. A cursory search of cupping jars which are still in common usage shows that there are a substantial variation of shape including spread/flared lip which is stated as being an aid to cleaning/drying.4. One 17th century source shows the type now raising controversy.5. Leach carriers are mostly illustrated with integral closures, the small glass jars with spread/flared rims being assumed generally to be leech carriers being an exception! An exception that affects practicality is an instant red flag.
a. Having to tie on a cover would be very inconvenient when a simple integral closure would be so simple to provide. b. Perhaps in years gone by patients were less squeamish but unlike most of the other leech carriers a glass jar would not conceal the creatures from the patient prior to their use.c. Lesser point, but I have seen no examples with a carrying case, most glass medical jars of specialised function intended for portability are often provided with such and these have remained.