Company Names, addresses, dates: ^1,2
  M.A. Santos, Norfolk VA (1819-c.1850s)
  M.A. Santos & Son, Main Street, Norfolk VA (c.1850s)
  M.A. & C.A. Santos, Nos. 3 & 5 Main Street, Norfolk VA (c.1850s-1868)
  M.A. & C.A. Santos, Atlantic Block, Norfolk VA (1868-c.1875)
  M.A. & C.A. Santos, No 118 Main Street, Norfolk VA (1872-1888)
  M.A. & C.A. Santos, 5 Bank Street, Norfolk VA (1889-1891)
  Santos Drug Store, 5 Bank Street, Norfolk VA (1892-c.1897)
  Santos Drug Store, 87 Bank Street, Norfolk VA (c.1898-1905)
  Chas O. Santos, 419 Williams Street, Norfolk VA (1920-1925)

Notes:
Manuel Anthony Santos (1795-1859)³ started a drug store in Norfolk in 1819².
By 1851¹, his son Charles Antonio Santos (1828-1896)⁴ was a partner in his business. Although Manuel died in 1859, the drug store continued to be called "M.A. & C.A. Santos" until 1892¹. His wife Eliza D. Santos continued to be a partner in the drug store until 1884, when Charles became the sole owner⁵, even though he didn't change the name until 1892.
Charles's obituary said he was part of the drug store business for over 50 years. It also said he remained in the city during a yellow fever scourge in 1855 to dispense medicine, and that he was once the president of the Pharmaceutical Society of Virginia.⁴.

Bottles:

This is an aqua, 5.8" unembossed bottle with a label: label: ... CASTOR OIL / FROM / M.A. & C.A. / SANTOS, / WHOLESALE / Druggists / Atlantic Block, / No. 118 Main Street, / 1,3, & 5 Atlantic Street, / NORFOLK, VA.

This is a 3" x 5.5" envelope. I can't read the year it was postally canceled, but it has an upside-down 1-cent stamp, so it's old. It says: Printed return address: ... / M.A. & C.A. SANTOS, / DRUGGISTS / NORFOLK, VIRGINIA / Wholesale Agents Forest's / Juniper Tar. hand written addressee: Mr.'s H.H. Hay & Son / Junc: Freq & Middle Sts / Portland / Maine