taino<l l)v Iiis predecessors, and of directinp into new fields of invest ipat ion the disciples who j)roHted by his su);tjestive teaching. To accuracy of observation he adiied such a K'asp of principles and so clear a com- prehension of the bearins of other sciences upon physiology that his reasoinn};, based thronKhout upon facts, is philosophical in breadth and penetration.
His first nionojfraph, an elaboration of his prize es- say, " De respiratione foetus", was published in 1823, and was followed (1S2G) by two others on optical illu- sions and on the comparative physiology of vision. The last-named abounds in observations upon the structure and functions of the eye in lower animals, especially in in.sects. Among the other subjects to which ^Iiiller devote<i careful and successful research may be mentioned: reflex action, the chemical com- position of blood i)lasma, the presence of chondrin in cartilage, hermaphroditism in human beings, the mi- nute structure and origin of glands in man and ani- mals, the lymph hearts of amphibia, and thoseductsof the jirehminary kidney in the fietus which have since been called by his name. His stud}' of the lower ani- mals resulted in the discovery of alternate generations and in a satisfactory account of the metamorphoses of echinodermata.
From 1834 to 1840 he edited the "Archives of Anat- omy and Physiology" (Midler's Archives) and con- tributed articles to various scientific reviews. His own contributions to medical literature number over two hundred, most of them of great significance. His principal work is the "Handbuch der Physiologic des Menschen", which was published in 1833 and has appeared in numerous editions and translations. But the benefit which he rendered to science as an original investigator and medical editor is surpassed by his work as a teacher. Among his pupils were most of the men who made Germany the Mecca for scientific students in the latter half of the nineteenth century. They included Virchow, lielmholtz, Schwann, Du Bois-Reymond, Lieberkilhn, Max Schidtze, Briicke, Claparede, Haeckel, Ilenle, Guido Wagener, Reichert, Ludwig, Vierordt, and KoUiker. All of these men agreed in proclaiming him the foremost physiologist of his time. Most of the important scientific societies of the world honoured him. Throughout his life he was loyal in his adherence to the Catholic Church, and his fellow-Catholics of the Rhine land have erected a noble monument to his memory at Coblentz.
ViBCHOw, Johann Mailer (Berlin, 185S): Brucke, Medical Times and Gazette (London, 17 July, 18.58); Dd Bois-Reymo.vd, Gedachlnissrede auf Johannes Mailer (Berlin. 1S60); Walsh, Makers of Modem Medicine (New York. 1910).
James J. Walsh.
Miiller (Regiomontanus), Johann, German as- tronomer, b. in or near Konigsberg, a small town in lower Franconia (Dukedom of Coburg), 6 June, 143(5; d. in Rome, 6 July, 1476. The name of the family agreed with the trade of the father who operated a mill. Regiomontanus signed himself Johannes de Monteregio, while in foreign countries he was known as Joannes Germanus or Francus. His calendars were published under various names, like Meister Hans von Kung.sberg. About the age of twelve he was sent to Leipzig to study dialectics. In the uni- versity matriculations (published by Erler, 189.5) his name is not registered. Hearing of the celebrated as- tronomer Peurbach (George of Peurbach in Upper Austria, 1423-61), I^Iuller left Leipzig for Vienna, where he was matriculated in 1450 as Johannes Mo- litoris de Kunigsperg. In 14.52 he received the bacca- laureate and in 14.57 the title Magisler. Lectures of his at the university are recorded as follows: in 145S on perspective, in 1460 on Euclid, in 1461 on Virgil's Bucolics. His master and friend Peurbach showed him how incorrect were the .Vlphonsine Tables and how false the Latin translations of the Greek astron- omers from intermediate Arabic translations. To-
gether they f)bserved the planet Mars two degrees off the place assigned to it and a lunar eclipse over an hour late on the Tables. A new field opened to the two astronomers with the arrival in Vienna of the Greek scholar Caiclinal Hcssarion of Trebizond, then papal legate I" I he (riiprnir. and his bnitlier Sigisniund, for the pui]iiisi' (if adjusting dilTcrences and uniting them against the Turks. Haxing changed to the Latin Rite, Bessarion mastered the Latin language like his own, and commenced translating Ptolemy directly from the Greek. On the other hand Peurbach was engaged in composing an epitome on Ptolemy's "Almagest". The double circumstance that neither of them was able to accomplish his task, the one for want of time, the other for not knowing Greek, brought about an agreement that Peurbacli shoidd accompany Bes- sarion to Italy together with Regiomontanus. Peur- bach died 8 .\pril, 1461, not yet thirty-eight years old, and left the "Epitome" to his pupil to be finished and published as a sacred legacy.
In company with his new patron, Miiller reached Rome in the Fall of 1461. UnderGeorge of Trebizond and other teachers he acquired so much knowledge of Greek that he understood all of the obscure points of the "Epitome" of his late master. During his stay in Italy Miiller continually observed the sun, the moon, and the planets, and searched the libraries for Greek manuscripts. He found another lunar eclipse over an hour in advance of the Tables. What manuscripts he could not acquire he had copied. A new Testament, written in Greek by his own hand, was his companion. The summer of 1402 was spent at Viterbo, and when Bessarion left for Greece in the Fall of the same year, Miiller accompanied him as far as Venice. On the recommendation of his patron, Midler was well re- ceived in various Italian cities. In Ferrara he be- came acquainted with an old friend of Peurbach, Bianchini, then ninety years of ago, with Theodore of Gaza, and with Guarini. He profited so well in the knowledge of Greek that he understood the whole of Ptolemy, and was able to complete the "Epitome" of Peurbach by adding seven books to the six already written by his master. In Padua he wiis at once en- rolled among the Academicians and was invited to lecture. While awaiting the return of his patron in Venice, he discovered a portion of the Greek Arith- metic of Diophantus, continued his observations, re- futed the quadrature of the circle given by Cuse, and computed a calendar with the places of sun and moon, the eclipses and the dates of Easter for the next thirty years. After two years' absence from Rome, Miiller returned there alone in October, 1464, to spend four more years in studying and copying. His rich col- lection of manuscripts comprised at that time Bes- sarion's own copy of the Greek "Almagest". Miiller was now able to point, out grave errors in the commen- taries on Ptolemy and Theon by George of Trebizond. The consequent enmity of the latter, and the absence of his patron, may have induced him to leave Italy in 1468.
The university registers in Vienna contain no record of Miiller ever resuming his lectures after his return. The next three years, or part of them, he seems to have spent in Buda, being recommended by the Arch- bishop of Gran to King Matthias Corvinus of Hun- gary as custodian of the library, so rich in spoils from Athens and Constantinople. The ensuing wars of the king in Bohemia led Miiller to look for a place where , he could carry out his life's plan: the determination of the astronomical constants by observation and the publication of the literary treasures in print. Niirem- berg, then the centre of industry and commerce in southern Germany, was his choice, and in the Fall of 1471 he was admitted to the city and even invited to lecture. A wealthy citizen, Bernhard Walther, fur- nished the means for an instrument shop, an observa- tory, and a printing office and joined Miiller in the