What were doctors looking for as they watched the immigrants climb the stairs?

Doctors were observing the immigrants for signs of illness or disease as they climbed the stairs, which was part of the medical inspection process at Immigration stations like Ellis Island. They were particularly vigilant for symptoms of contagious diseases such as tuberculosis or cholera, which could pose a public health risk. The goal was to ensure that only healthy individuals were allowed to enter the country, thereby protecting the broader population.