Arthur resumed his medical training and then joined the Royal National Mission to Deep Sea Fishermen, working as one of only two qualified doctors on the Labrador Coast in Eastern Canada.
In 1914 he was instrumental in recruiting the first 500 volunteers for the Newfoundland Regiment, one of many such regiments raised across the Commonwealth and Empire. At that time Newfoundland was not part of Canada and took great pride in raising its own regiment so quickly. Like Arthur, many of those who joined had previously served with the British or Imperial forces in the Boer War.
The photograph showing the Regiment’s first officers with their Prime Minister and Governor General has many in the uniforms of their peacetime militia (reserve) regiments. The first recruits were nicknamed the "Blue Puttees" due to the unusual colour of the puttees, chosen to give the Newfoundland Regiment a unique look, but quickly abandoned when the first 500 reached England in October 1914.