Borelli, Giovanni Alfonso, 1608-79, Italian physiologist, physicist, astronomer, and mathematician; son of a Spanish infantryman. His wide interests led to original contributions in many fields, including anatomy, epidemiology, the study of fermentation, volcanology, magnetism, fluid dynamics, and the observation of comets. In his study of disease he concluded, against most contemporaries, that meteorological and astrological causes were not at work, but that something entered the body and could be remedied chemically. In Euclides restitutus he reworked Euclid's Elements into a more concise form. He is perhaps best known for his De motu animalium (1679), a study of the mechanical basis of respiration, circulation, and muscular contraction in animals.