Earlier, in the 1830s, Robert Koch, a scientist, had said that cholera was being caused by a bacterium that entered the human body through water and food.
(a bacterium; entered; the human body) (Robert Koch; had said; that cholera was being caused by a bacterium; T:Earlier; L:in the 1830s) Context(Robert Koch had said,List([23, 57))):(cholera; was being caused; by a bacterium) (Robert Koch; [is]; a scientist)
Robert Koch had said,List([23, 57))
a bacterium Robert Koch cholera Robert Koch
entered had said was being caused [is]
the human body
that cholera was being caused by a bacterium T:Earlier L:in the 1830s
by a bacterium
a scientist