Weir Mitchell's 1859 demonstration of "a peculiar contraction" produced by a percussion hammer

BACKGROUND: The 1875 publications of Erb and Westphal brought widespread attention to the percussion of muscle stretch reflexes. Although the maneuver may have been observed before 1875, there is little concrete evidence of this. OBJECTIVES: To bring to light an early report of percussion eliciting the muscle stretch response. METHODS: While studying the Weir Mitchell papers (Philadelphia College of Physicians), the author came across an early report of the maneuver. RESULTS: The 531-word 1859 report, published in the Proceedings of the Academy of Natural Sciences of Philadelphia, was written by a pro tem reporter who observed Mitchell's demonstration of the phenomenon. The other attendees, including Dr. William Hammond, were so well aware of the phenomena that Dr. Mitchell "did not consider it necessary to describe them more fully." Mitchell viewed the response as muscular in nature and the relationship between this response and disease was not explored in the report. CONCLUSIONS: This 1859 report preceded the Erb and Westphal publications by nearly two decades. It is perhaps the first concrete proof that neurologists were observing this phenomenon as early as the mid-1800s. Mitchell viewed the phenomenon as a local muscle response. While the concepts that later allowed Erb to correctly interpret the phenomenon as a reflex arc were already in place, Mitchell did not synthesize these concepts.