142 VEGETABLE SUBSTANCES. 



long in water as the best oak; and the bark is tough 

 and fibrous, and may be made into strong and dura- 

 ble mats and baskets. 



The greatest value of the mulberry-tree in the arts 

 consists in its being the favourite food of the silk- 

 worm. That insect, and this use of the mulberry- 

 tree, were both unknown to the Greeks and Romans; 

 though there is every reason to believe that they 



Blade Mulberry Morus nigra. 



were then, and perhaps earlier, known to the Chi- 

 nese, and possibly to some of the other inhabitants 

 of central and southern Asia. 



The rearing of silk-worms, and the manufacture of 

 silk, are said to have been introduced into the West- 

 ern world in the sixth century of the Christian era. 

 About the year 550, two monks, natives of Persia, 

 while employed as missionaries to the Christian 

 churches in India, are said to have penetrated as far 

 as China, where they acquired a knowledge of the 

 rearing of the silk- worm, and the working of silk. 

 Upon their return, they explained to the Greek em- 

 peror at Constantinople the nature and importance 

 of those operations, and undertook to bring to that 

 capital as many silk-worms as should suffice for esta- 



