https://patents.google.com/patent/US454138A/en
This nipple is adapted for insertion into the ear, and is ordinarily covered with a rubber cover to lessen the friction against the orifice of the ear.
https://patents.google.com/patent/US454138A/en
This nipple is adapted for insertion into the ear, and is ordinarily covered with a rubber cover to lessen the friction against the orifice of the ear.