Menus received his medical education at Queen’s University, Cork, qualifying M.D., R.U.I in 1880. On 5th February 1881 he took up a commission in the Army Medical Services at the rank of Surgeon Captain. He served in Egypt in 1882, then gained promotion to the rank of Major in 1893, and served in the N W Frontier, India, from 1897 to 1898. On 5th February 1901 he was promoted to the rank of Lieutenant Colonel, then gained promotion to Colonel on 23rd April 1910. He married a Belfast Lady, and for a while was stationed there. From 28th July 1910 to 4th March 1914 he served as Inspector of Medical Services on the staff of the Inspector-General of the Forces. He was placed on half-pay on 23rd April 1914.
He was mobilized when war broke out on the staff of Surgeon-General Woodhouse, as his Deputy Director of Medical Services [D.D.M.S.] on the Lines of Communication. He proceeded to France from Southampton on the 9th August 1914, entering the war in France at Havre the following day. He remained in Havre, where he set up an office, until 18th August.
On 16th September 1914 he was appointed D.D.M.S., Third Corps, which had not long been formed. He arrived for duty on the 19th September.
From 6th January 1915 to 25th February 1916 he served as D.D.M.S. with the Cavalry Corps, then was appointed Director of Medical Services [D.M.S.] of the Fourth Army on 26th February 1916. During this time, on 1st March 1915 he was promoted to the rank of Surgeon-General, and was created Commander of the Bath [C.B. (mil) 1916]. In 1917 the Tsar’s Government gave him a First Class Order of St Anne with crossed swords.
On 5th November 1917, his office moved from Malo-les-Bains to Dury, near Amiens, but the D.M.S., 2nd Army proceeded with the 2nd Army Headquarters to Italy a few days later, on the 16th, and he took over his duties in the Ypres area. He rejoined as D.M.S. Fourth Army on 2nd April 1918. In 1918 he was created a Knight Commander of the Order of St Michael and St George. He was also awarded the Legion of Honour by the French Government as recognition of his services.
He retired from service in 1919, and moved to Camberley in 1925, where he became President of the Round Table in Camberley. In 1927 was appointed an honorary post of Colonel-Commandant R.A.M.C.
He died at Abbeywood in Camberley, and was buried on 2nd December 1944.