He pioneered aseptic surgery (having once shared lodgings with Joseph Lister), and, in 1880 invented Gamgee Tissue, an absorbent cotton wool and gauze surgical dressing.

[1] His classmate was Joseph Lister with whom he shared lodgings and considered him a close friend.

[3] In 1868 he was elected a Fellow of the Royal Society of Edinburgh his proposer being Sir James Young Simpson.

In 1886 his health further worsened during a trip to Dartmouth where he fell fracturing his right femur at its head.

[1] He gave his name (indirectly, via the tissue) to the hobbit Sam Gamgee in J. R. R. Tolkien's The Lord of the Rings.