2 BULLETIN 404, U. S. DEPAETMENT OF AGEICULTUEE. 



The hemp stalk grown in, a, broadcast crop for fiber production is 

 from one-eighth to three-eightiis of an inch in diameter and from 4 to 

 10 feet tall. The stalk is hollow, with a cylindrical woody shell, thick 

 near the base, where the stalk is nearly solid, and thinner above, where 

 the hollow is relatively wider. 



In the process of breaking, the woody cylinder inside of the fiber- 

 bearing bark is broken into pieces one-half of an inch to 3 inches long 

 and usually split into numerous segments. The thicker lower sec- 

 tions are split less than the thin-shelled upper ones, and they are often 

 left quite solid. 



PITH, WOOD, AND FIBER. 



The inner surface of the hurds usually bears a layer of pith, consisting 

 of thin-walled cells nearly spherical or angular, but not elongated. 

 They are more or less crushed and torn. They are probably of little 

 value for paper, but they constitute less than 1 per cent of the weight 

 of the hurds. The principal weight and bulk consist of slender elon- 

 gated woody cells. The outer surface is covered with fine secondary 

 fibers composed of slender elongated cells, tougher than those of the 

 wood but finer and shorter than those of the hemp fiber of commerce. 

 No method has been devised thus far which completely separates 

 from the hurds all of the long fiber. From 5 to 15 per cent of the 

 weight of the hurds consists of hemp fiber, in strands from 3 inches 

 to 8 feet in length. Some fragments of the bark, made up of short 

 cubical cells, usually dark in color, cling to the strands of fiber. 



CHARACTER OF HURDS AFFECTED BY RETTING. 



Nearly all of the hemp in the United States is dew retted. The 

 stalks are spread on the ground in swaths, as grain is laid by the cradle. 

 The action of the weather, dew, and rain, aided by bacteria, dissolves 

 and washes out the green coloring matter (chlorophyll) and most of 

 the gums, leaving only the fibrous bark and the wood. The plants in 

 this process lose about 60 per cent of their green weight, or about 40 

 per cent of their air-dry weight. 



The stalks are sometimes set up in shocks to cure before retting, 

 and after retting they are set up in shocks to dry. Each time the 

 stalks are handled they are chucked down on the ground to keep the 

 butts even. In these operations sand and clay are often driven up 

 into the hollow at the base of the stalks, and this dirt, which often 

 clings tenaciously, may constitute an objectionable feature in the use 

 of hemp hurds for paper stock. 



In Italy and in most localities in Russia and Austria-Hungary 

 where hemp is extensively cultivated, it is retted in water, but water 

 retting has never been practiced in the United States except to a 

 limited extent before the middle of the last century. Hurds from 



