For more than a century, we could see Florence Buchanan’s science but not Florence Buchanan. Her papers and electrical traces survived, and her work placed her alongside some of the most influential physiologists of the early 20th century. Yet until recently, no authenticated portrait of Buchanan was known.

Our recent research has now recovered that missing face. There is an irony here: Buchanan used sensitive recording instruments to turn the tiny electrical changes accompanying muscle activity into visible traces. These recordings allowed her to measure events too brief for the eye to follow, helping her investigate how signals travelling through nerves produce a muscular response.

In 1908, Buchanan published a study of spinal reflexes in frogs. It was the opening paper in the first volume of The Quarterly Journal of Experimental Physiology. Using a capillary electrometer, an early electrical recorder that turned tiny voltage changes in muscle into photographic traces, Buchanan could distinguish an immediate muscle response from a later reflex that had travelled into and back out of the spinal cord.

After allowing for the time taken by signals travelling along peripheral nerves, she estimated that a frog’s spinal cord introduced a delay of roughly 12 to 22 milliseconds. Her measurement captured the overall delay produced within the spinal cord during the reflex. Later research was able to separate the different processes contributing to that interval, showing that transmission across an individual synapse, the junction where one nerve cell passes a signal to another, could take far less........

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