Complex sentence: Van Helmont's work included defining operations of the body in chemical terms, claiming that iatrochemists stress the chemical reactions of effervescence, fermentation, and putrefaction as the basis of all physiology.
Split into simpler sentences: Van Helmont's work included defining operations of the body in chemical terms. He described the body's functions as the chemical reactions of effervescence, fermentation, and putrefaction as the basis of all physiology.