[3] In the 1860s, he improved on the design of the syringe that had been invented by Alexander Wood by adding the needle point and lateral opening.
[5] Hunter initially followed Wood's method of using syringes to inject morphine locally, into the area where pain was located.
[6] After conducting tests on animals to establish his findings, Hunter campaigned for the "general therapeutic effect" of what he initially called the "ipodermic" method, later inventing the term "hypodermic".
[6] Francis E. Anstie also recommended Hunter's method, proclaiming that there was absolutely no danger in administering opium hypodermic injection.
His early death and Wood's popularity meant that Hunter's legacy in the history of medicine has not endured particularly well by comparison.