This brass instrument was used to tattoo deserters with the letter "D". When the spring was pulled the needles, in the formation of a D, pierced the prisoner's skin. Gun-powder was then rubbed into the wound in order to create an indelible mark which announced the bearer's perfidy. At one time the military doctors were ordered to tattoo the men. Their reaction is expressed by William Munro when he writes in his autobiography, Records of Service and Campaigning in Many Lands (London: Hurst and Blackett, 1887):
We were all very indignant at this, for we did not consider it any part of the medical officer's duty to inflict punishment on the soldier.
Eventually the "insulting and degrading order" was repealed.
