Those of us who have studied First World War service will be very familiar with men being discharged under paragraph 392 (xvi) of King's Regulations for 1912 (re-printed with amendments to 1st August 1914). Men who were no longer physically fit for war service were discharged under this regulation and this particular form is essentially confirmation of this by the Medical Board.
These forms were printed in booklets and then detached. A note at the bottom of this particular form shows that it was part of a run of 8000 booklets which were printed in August 1916 (a month or more after the opening of the Somme offensive), clinical pessimism about the number of men who would soon be passing through this particular process.
This particular form was issued for 33179 Pte Ernest Riches of the 10th Yorkshire Regiment who was discharged from Norfolk War Hospital, Thorpe on the 30th August 1917.
The image on this page is Crown Copyright, The National Archives.