in the body. furthermore, while iatrophysicists rejected acid-base theory as an explanation for bodily processes, iatrochemists embraced the theory. influence on medicine in the middle ages, galenic anatomo-physiology prevailed as the leading medical thought. furthermore, aristotelian natural philosophy had dominated for centuries, including the humoral system as a primary method of medical thought. however, the philosophies of aristotle, hippocrates, and galen began to wane in popularity, replaced by anatomical and philosophical schools of thought based on mechanics and chemical naturalism. ideologies such as iatrophysics and iatrochemistry began to prevail. the decline of galenic philosophy-based medicine coupled with the rise of new ideologies was spurred by the advent of new discoveries in anatomy and physiology, such as that of william harvey's work centered on circulation of the blood. his idea that pulse, respiration, and nutrition were all working components of a unified system revolutionized preexisting ideas about blood, nutrition, and heat. the discovery of the circulation of the blood was crucial in the development of iatrophysics in that it was the first that related “circulations” to physiological functions. this led to the advent of new discoveries such as the circulation of nutritive fluid, circulation of lymph, and circulation of nervous juice, all of which relate a machine-like mechanism to anatomy. traditionally, physiological functions were believed to be regulated by purposeful tendencies. however, the advent of the new medicinal schools of thought transformed the way physiology was approached. secretion and excretion were no longer due to attractive tendencies, the function of the lungs were now due to the mixing of different parts of the blood, digestion was seen as a process of grinding and mincing, and health and disease were associated with movement, obstruction, and stagnation of the various bodily fluids running through the body. the body increasingly became viewed as a function of a machine, especially with the development of isaac newton's theory of gravitation and motion. newtonian physics came to widely influence the way the body was viewed, and physiology was increasingly focused on a clockwork mechanism, and the later hydraulics was even applied to the movement of bodily fluids. furthermore, with the publication of newton's opticks in 1704, physiologists increasingly depended on the notions of ether and effluvia in their anatomical observations.