Answer:
He tested on prisoners in jail and used them on patients.
Step-by-step explanation:
Dr Goldberger discovered that Pellagra was caused by malnutrition when he tested his patience. He made them go on an unhealthy diet for weeks on just corn starch, and then after they got Pellagra, he cured them by giving out nutrients to them. The US government saw Dr Goldberger's work and added nutrients to food. Pellagra is still contracted in developing countries, but can easily be cured thanks to Doc Goldberger.
