Harvey Washington Wiley, the brusque and determined leader of the Department of Agriculture‘s Bureau of Chemistry in Washington, D.C., had good news and bad news for the 12 young men who had answered his call for volunteers. First, Wiley promised them three ample, freshly prepared meals every day for at least six months. Since the majority of the men were Department clerks living on modest wages, this was a tempting offer. The volunteers would also be under exceptional medical care, with weekly physicals and daily recordings of their weight, temperature, and pulse rate.
This was, Wiley explained, because he‘d be slowly poisoning them.
Jake Rossen in Mental Floss.