Complex sentence: In 1899 he described a bacteria living in the human stomach named by him "Vibrio rugula", he has speculated that it is responsible for stomach ulcers, gastric cancer and achylia.
Split into simpler sentences: In 1899 he described a bacteria living in the human stomach that he named "Vibrio rugula". He speculated that it was responsible for stomach ulcers, gastric cancer and achylia.