The Potato That Could Forecast the Weather: Frank A. Brown Jr.'s Exogenous Clock
If you've spent any time in cycles research, you've run into the standard story of biological rhythms: every organism carries its own internal clock, a self-winding mechanism ticking away independent of the outside world. Through the 1950s and 60s, one Northwestern University biologist quietly built a career-long case that this story was, at minimum, incomplete.
Frank A. Brown Jr., Morrison Professor of Biological Sciences at Northwestern and a Consultant at the Marine Biological Laboratory in Woods Hole, wasn't a fringe figure. He was Vice President of the American Society of Zoologists, President of the Society of General Physiologists, and — worth noting for this community — an elected Director of the Foundation for the Study of Cycles from 1960 onward. His papers ran in PNAS, Biological Bulletin, and the American Journal of Physiology. And his experiments were genuinely strange.
The fiddler crab. Brown's earliest work showed that fiddler crabs, which darken and lighten daily via pigment movement, kept perfect 24-hour rhythm even sealed in total darkness at 26°C, 16°C, or 6°C — as if something outside the box was still reaching them.
The potato that predicted pressure. This is the one that made the New York Times (April 17, 1959). Brown sealed pieces of potato — no nervous system, so no behavioral tricks possible — in hermetically closed, constant-condition chambers and tracked their oxygen consumption continuously for over two years. Two results stood out: a lunar-monthly rhythm in metabolic rate (lowest at new moon, peaking at third quarter), and — stranger still — a metabolic rate that tracked barometric pressure roughly two days before that pressure actually arrived. Salamanders in a parallel study showed the same anticipatory pattern.
The oysters that moved their tides inland. Maybe the best story of all. Brown took oysters from New Haven, Connecticut — where they naturally open their shells at high tide — and shipped them to landlocked Evanston, Illinois. Over time, the oysters shifted their opening schedule to match the high tide Evanston would have, if Evanston were on the coast. No tide, no obvious cue — just a slow drift toward a rhythm keyed to a force nobody could point to directly.
Magnetism, into the '60s. By 1962, working with geologist Karl C. Hammer, Brown reported that snails, worms, and the single-celled paramecium could detect magnetic fields, and that the planarian worm Dugesia even distinguished north from south poles. By 1964 he was writing directly for Cycles Magazine on the topic ("How Animals Respond To Magnetism"), and the Foundation was floating the idea that regular fluctuations in the earth's magnetic field might be a hidden driver behind some of the cycles the FSC had been cataloguing for years.
The jet-lag note. Almost in passing, Cycles (March 1963) cited Brown's observation that a person flown from California to England keeps their body clock — waking pattern, temperature, blood cell counts, hormones — running on California time for eight to ten days before it resets. This is, essentially, an early clinical description of jet lag, years before the term existed.
Brown's proposed mechanism — that organisms are entrained by very weak geophysical signals like barometric pressure, cosmic radiation, and magnetism, rather than running on a purely self-contained clock — lost out to the now-dominant endogenous-clock model in chronobiology. But he wasn't wrong that something was going on in his data, and he was never a crank: credentialed, published, elected. For anyone interested in the roads not taken in cycle science, he's a genuinely interesting figure to dig into further.
Sourced from Cycles Magazine, 1959–1964 (Vols. 10–15), Foundation for the Study of Cycles.