The following items are an inventory of Dr. Watson's personal effects:

General:

Bull pup (STUD)
Pencil (STUD)
Valise (BOSC)
"very excellent field-glass" (SILV)
muffler (RESI)
calling cards (NAVA)
matches (FINA)
buys carpetbag in (FINA)

Books & Magazines:

Henri Murger's "Vie de Bohème" (STUD)
A Charles Darwin publication (likely Darwin's On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life) (STUD)

Shakespeare's Hamlet British Medical Journal (STOC)

Firearms & Ammunition:

Service Revolver from his military days (STUD, SIGN ). Scholars have argued that this might be an Adams No. 3 (D.M. Torese) or Adams .450 (Baring-Gould)

"Eley's No. 2" (actually a type of ammunition). Which actually handgun this refers to is unclear. (SPEC)

Webley's No. 2, a candidate for the "Eley's No. 2" that Watson owns)

Consulting Room & Medical Items:

Stethoscope (secreted in right side of top hat) (SCAN, SIGN)
Iodoform (compound of iodine used as antiseptic) (SCAN)
Nitrate of Silver (antiseptic & disinfectant) (SCAN)
books (ENGI)
table (ENGI)
side table (ENGI)
carafe of water (ENGI)
brandy (ENGI)
cotton wadding (ENGI)
carbolized bandages (bandages with carbolic acid or phenol for use as antiseptic) (ENGI)

At His House with Mary:

table and lamp upon it (where he reads) (FINA)
house has shutters (FINA)
garden wall (outside) (FINA)