Ferguson spring lancet
Ferguson lancet
Leather box with red velvet lining containing an unusually shaped spring lancet by Ferguson.  Ferguson was a London instrument maker from 1822-1858. He was the instrument maker at  St Bartholomew's Hospital, London for many years.

Extra blades are present under the bottom of the case.
Makers mark
Blade stay mechanism
Note the inner workings of the unit and compare them to the large unmarked veterinary piece in the Shagreen case.  Very similar craftsmanship.