Giovanni Alfonso Borelli, an Italian mathematician and physician, born at Castelnuovo, near Naples, Jan. 28, 1608, died in Rome, Dec. 31, 1679. He was professor of mathematics in Messina and in Pisa, became in Rome a favorite of Queen Christina of Sweden, taught mathematics (1677-'9) at the convent of St. Panta-leon, and was a member of the accademia del Cimento. He was one of the leaders of the iatro-mathematical school, and employed himself diligently in the dissection of animals with a view of explaining their functions upon mathematical principles. He invented a diving apparatus, excelled as an astronomer, wrote extensively on medicine, mathematics, and astronomy, and also published a scientific account of the eruption of Mt. Etna (1669). The first part of his principal work, De Motu Anima-lium (2 vols., Rome, 1680-'81), skilfully applies the principles of mechanics to the exposition of the movements of the body; but the second part is regarded as fallacious in respect to the application of mechanical principles to the action of the heart, lungs, liver, and other viscera.

This work was long regarded as a standard authority by the iatro-mathematical school.