FIBRES. 283 



in length, with equal fineness; the longer the fibre, the 

 better. The width varies between .001 77-02440. The color 

 is a light blonde to gray or yellowish. The best Flax is 

 very lustrous ; that which is lustreless is contaminated with 

 cortical parenchyma. When air-dry, it contains 5.7 to 7.2 

 per cent, of water. The bast-cells, of which it is composed, 

 have pointed ends and walls so thick, that the cavity is 

 almost closed ; their length is 8-16 inches, their maximum 

 width .00047-.00102, and commonest width .00059- 

 .00067 inches. They are not bleached till after their 

 manufacture into cloth, 



262. The very important textile fibre. Hemp, consists 

 of the bast of Cannabis sativa, a dioecious species of the 

 Nettle family ( UrticaceoR), growing six to twelve feet high, 

 having large pedate leaves, with five leaflets and incon- 

 spicuous flowers. It is supposed to be a native of the warm 

 parts of Asia, and is found in cultivation in Africa, North 

 America, Australia, and elsewhere. It has been used in 

 Europe several hundred years. It must be harvested for 

 the fibre before maturity of the seed ; the latter can then 

 be used for obtaining oil. The pistillate plants when 

 grown for the seed must be allowed to ripen. The process 

 of retting is similar to that employed in case of Flax., The 

 fibre of Hemp is longer and coarser than that of Flax. 

 The color is often white, but the gray is the best. It is lus- 

 trous. The cells of the fibre are tworfifths of an inch or 

 more in length, with mostly obtuse ends, and in transverse 

 section are round. The cavity of the cell is about one- 

 third its diameter; width of the latter, .00059-00110 

 inches. The Hemp plant is used as an intoxicant for chew- 

 ing and smoking by over three hundred million people. Its 

 narcotic efiect is due to a gum-resin existing in the leaves 



