He received house appointments in Glasgow Royal Infirmary and then the Northern Hospital, Liverpool, settling in Everton at that time.

Working at Kirkdale Gaol in Liverpool as a Medical Officer he developed a strong interest in the care of prisoners, leading him to be sent to Ireland by the British Government in 1885 during a period of unrest.

[2] He gave evidence to the Capital Sentences Committee (sitting 1886-1888) and in 1891 was involved in the training of the first three hangmen who were put on the list of persons competent to perform executions.

"[5] In a 1918 speech, Barr said that tuberculosis "forms a rough, but on the whole very serviceable check, on the survival and propagation of the unfit" before concluding: "...if to-morrow the tubercle bacillus were non-existent, it would be nothing short of a national calamity.

"[6] He was Vice President of the Society of Constructive Birth Control and Racial Progress and a strong supporter of its founder Marie Stopes.