He had to consult were the

The Great Boer War is a non-fiction work on the Boer War by Arthur Conan Doyle and first published in 1900 by Smith, Elder & Co. By the end of the war in 1902 the book had been published in 16 editions, constantly revised by Doyle. The Introduction describes the book as:

A very thorough account, including tables at the end of those killed or wounded up until the 8th September when he left South Africa. This account is compiled with as much accuracy as was attainable at this date, and with as much detail as a single volume will permit. In frequent conversations with Boers, Conan Doyle has endeavoured to get their views upon both political and military questions. Often the only documents he had to consult were the convalescent officers and men under his care, therefore some errors may have crept in. The closing scenes of the Boer War have necessarily been treated with less detail than the earlier.

Manual labour or manual work is physical work done by humans, in contrast to labour by machines and working animals. It is most literally work done with the hands and, by figurative extension, it is work done with any of the muscles and bones of the human body. For most of human prehistory and history, manual labour and its close cousin, animal labour, have been the primary ways that physical work has been accomplished. Mechanisation and automation, which reduce the need for human and animal labour in production, have existed for centuries, but it was only starting in the 18th and 19th centuries that they began to significantly expand and to change human culture. To be implemented, they require that sufficient technology exist and that its capital costs be justified by the amount of future wages that they will obviate. Semi-automation is an alternative to worker displacement that combines human labour, automation, and computerisation to leverage the advantages of both man and machine.