As the early 19th century law restricting medical employment in the British military to those who had qualifications in both medicine and surgery was taken to require diplomas from different organisations, it became customary to take both the Licence of the Society of Apothecaries (LSA) and the Membership of the Royal College of Surgeons of England (MRCS).
The nomenclature of the diplomas may have contributed to the nearly-obsolete practice of general practitioners styling themselves as "Physician and Surgeon": previously they were mostly regarded as Apothecaries.
This paralleled the practice in some European countries of taking a state medical examination separately from or instead of a university degree.
The scheme of examinations included a notional full set of pre-clinical subjects (anatomy, physiology, pharmacology, pathology, etc.)
These subtleties of the British system of medical qualifications were rarely known to patients, who may have been more impressed to see "MB BS MRCS LRCP" on a brass plate than "MD FRCP".