Device to prevent mouth breathing

In 1920, Richard Jefferies was granted a patent for "a simple and practical device which will eliminate the habit of breathing through the mouth and at the same time will assist in harmonizing the facial features of the wearer, by more evenly balancing the muscles of expression."

His invention consisted of a piece of adhesive-backed silk placed over the mouth.



I was vaguely aware that mouth breathing is considered a bad habit, but I wasn't aware that "mouth taping" continues to be a common remedy for it.

For instance, one can buy SomniFix Sleep Strips, which look like they're a slightly updated version of Jefferies' invention.