M.R.C.P., Member of the Royal College of Physicians.
M.R.C.S., Member of the Royal College of Surgeons.
M.R.C.V.S., Member of the Royal College of Veterinary Surgeons.
M.R.I., Member of the Royal Institution.
M.R.I.A., Member of the Royal Irish Academy.
MS., Manuscript.
MSS., Manuscripts.
Mus. Doc., Doctor of Music.
N.B., Mark well.
Nem. con., Without opposition.