,, 4 NATURAL SCIENCES. 



relating their journeys, did not merely record what struck them the most in 

 the way of plants, animals, and stones ; they brought back to Europe speci- 

 mens which might be of use to science, and serve to correct anything inco- 

 herent or exaggerated in what they had written. The most celebrated Indian 

 explorer of the thirteenth century, Marco Polo, the Venetian, who passed 

 more than twenty years in those then unknown lands, and who penetrated as 

 far as China, has left a very curious account of his long journeys, in the 

 course of which he relates all that he saw or heard. Natural history occupies 

 a large place in his story, which but too often testifies to his ignorance and 

 credulity. (See below, chapter on Geographical Sciences.) 



The most prominent botanists of that period, always in regard to the 

 materia medica, were : two Englishmen, Gilbert and Hernicus Arviell, who 

 travelled, the one through Eiirope, the other through Asia, to study plants 

 and prepare treatises on botany ; Simon de Cordo, called Simon of Genoa, 

 who had undertaken a herborising expedition into the islands of the Archi- 

 pelago and to Sicily, and who, borrowing largely from the Greek and Arab 

 writers, compiled a Botanic Dictionary ; and Jean de St. Amand, Canon of 

 Tournay, who proceeded experimentally to his discoveries in therapeutics, 

 and devoted a remarkable work to the research of the medicinal properties of 

 a certain number of simples. But the most learned and experienced of these 

 botanists of the thirteenth century was Peter de Crescenzi, or de Crescentiis, 

 born at Bologna in 1230, a man of mark both in regard to birth and fortune, 

 who had a great predilection for agriculture and horticulture, and who, 

 adding to his own observations all that the ancient authors and those of the 

 Middle Ages had written about the vegetable productions of nature, com- 

 piled a sort of agronomical encyclopaedia called " Opus Ruralium Commo- 

 dorum." This great work, replete with information, judicious advice, and 

 excellent practical notions, was translated into several languages, and 

 especially into French, by order of King Charles V., and called " Livre des 

 Proufnts champestres et ruraux." 



Peter de Crescenzi treated but one side of natural history, but three of 

 his contemporaries, Vincent of Beauvais, Albertus Magnus, and Arnaud de 

 Villeneuve, entered upon the study of this science in a spirit of observation 

 which embraced all its aspects. They were, in fact, astrologers, alchemists, 

 theologians, and physicians first ; naturalists afterwards. Vincent of Beau- 

 vais, a Dominican monk, who had translated the story of the voyage of John 



