Simpson introduced many important procedures into gynecology and obstetrics; among them may be mentioned his use of the uterine sound for diagnosing retro-positions of the uterus

In an attempt to find an anesthetic less irritating than ether, Simpson discovered the advantages of chloroform. He had previously used ether with great benefit in midwifery, but now substituted chloroform, being the first to do so. Preliminary announcements in Lond. med. Gaz., 1847, n.s. 5, 906.

Digital facsimile of the first part from PubMedCentral at this link, and of the second part at this link. Concluded with Simpson's "General observations on the Roman medicine-stamps found in Great Britain," Mon. J. Med. Sci., 16 (1851) 338-354 of which a digital facsimile is available from PubMedCentral at this link.

In 1858 Simpson described a new method of controlling blood loss during surgical operations – acupressure, not to be confused with the traditional Chinese medical technique similarly named. Simpson's technique, though developed further and found successful, failed to gain Simpson the recognition he was expecting. Simpson succeeded in creating a vogue for acupressure that lasted at least thirty years, though it did not lessen the mortality rates in British hospitals.

Digital facsimile from Google Books at this link.