"On the trail of the mercy bullet": Pain, scientific showmanship, and the early history of animal tranquilizing, c. 1912-1932.

In June 1928, Captain Barnett W. Harris, an amateur naturalist from Indiana, arrived in Zululand to experiment on wild animals with his invention - the mercy bullet. This "bullet"consisted of a hypodermic needle filled with anesthetic drugs that could render an animal unconscious - an early model of what is now known as the tranquilizer gun. The history of this gun typically begins with Colin Murdoch, a New Zealand pharmacist and veterinarian, who patented the invention in 1959. While largely absent in the archives, through tracing popular science publications and press, this article exposes a longer history of animal tranquilizers from an unlikely source. Tracing Harris's story allows this article to speak to different historical discourses that influenced his rise as a celebrated inventor, and later to his disappearance from the scientific arena. This article argues that debates about pain relief (for both humans and nonhuman animals) and developments in military technology at the turn of the twentieth century resulted in experiments with narcotic bullets, a precursor to this "mercy bullet moment." While hailed across the press as the man who might transform animal capturing into a humane practice, the workings of Harris's bullet remained ambiguous. Despite this, he promoted his invention through several lecture series and radio presentations to the American public in the 1930s, where elements of scientific showmanship can be observed. Overall, Harris's omission from the history of animal tranquilizing demonstrates the multiple contingencies that define a moment of scientific "success" - or, in this case, push some into relative obscurity.