A HISTORY OF SCIENCE 



where he was unable to study them with the naked 

 eye he used glasses for the purpose, and resorted 

 to macerations and injections for the study of certain 

 complicated structures. But while the fruit of his pen 

 and pencil were lost for more than a century after his 

 death, the effects of his teachings were not; and his 

 two pupils, Fallopius and Columbus, are almost as well 

 known to-day as their illustrious teacher. Columbus 

 (1490-1559) did much in correcting the mistakes 

 made in the anatomy of the bones as described by 

 Vesalius. He also added much to the science by 

 giving correct accounts of the shape and cavities of 

 the heart, and made many other discoveries of minor 

 importance. Fallopius (1523-1562) added considera- 

 bly to the general knowledge of anatomy, made sev- 

 eral discoveries in the anatomy of the ear, and also 

 several organs in the abdominal cavity. 



At this time a most vitally important controversy 

 was in progress as to whether or not the veins of the 

 bodies were supplied with valves, many anatomists 

 being unable to find them. Etienne had first described 

 these structures, and Vesalius had confirmed his ob- 

 servations. It would seem as if there could be no 

 difficulty in settling the question as to the fact of 

 such valves being present in the vessels, for the 

 demonstration is so simple that it is now made daily 

 by medical students in all physiological laboratories 

 and dissecting-rooms. But many of the great anato- 

 mists of the sixteenth century were unable to make 

 this demonstration, even when it had been brought to 

 their attention by such an authority as Vesalius. 

 Fallopius, writing to Vesalius on the subject in 1562, 



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