Complex sentence: Jesse Francis McClendon (December 21,1880--November 22,1976) was an American chemist, zoologist, and physiologist, best known for the first pH measurement of human stomach "in situ".
Split into simpler sentences: Jesse Francis McClendon (December 21,1880--November 22,1976) was an American chemist, zoologist and physiologist. He is remembered today mainly for the first pH measurement of human stomach "in situ".