BUREAU OF PLANT INDUSTRY. 417 



soda recovery must be worked out or methods of cooking must be 

 devised which will make recovery unnecessary. Rice-root grass tops 

 (a waste product of the zacaton root-brush fiber industry) have 

 yielded an especially promising pulp, closely related to that of poplar. 

 The hemp materials are especially promising. The corn-pulp yields 

 were the most satisfactory thus far obtained. Lack of funds pre- 

 vented the consunnnation of plans to experiment with pith pulp for 

 the manufacture of paper specialties. 



Production of food extract. — Sixteen cornstalk extractions were 

 made in large rotary digesters of 3,000 pounds capacity. Between 

 '800 and 900 gallons of extract were produced, containing about 40 

 per cent of solids. In cooperation with the Bureau of Animal In- 

 dustry, the extract was used in feeding 8 milch cows. The experi- 

 ment 'was continued over a period of 110 days and gave encouraging 

 results. 



In connection with the production of extract a large quantity of 

 pulp was produced. A test of the resistance of cornstalk pulp has 

 been carried on with this material. It was stored wet and unbleached 

 in a drainer and wet down from time to time. After eight months of 

 wet storage, paper of good quality is still being produced from it. 

 The stored pulp has been found to bleach more readily than that 

 worked up immediately after cooking. 



Plans for future work. — During the ensuing year especial atten- 

 tion will be given to flax-straw investigations in the hope of finding 

 suitable methods of handling the raw material and of cooking and 

 bleaching the same. Hemp stalks, both retted and uiiretted, and 

 hemp wastes will receive attention. Other work will include a study 

 of the individual variables in the cooking of different materials and 

 a critical comparison of the celluloses obtained from them. Tests will 

 be made of corn pith for making various pulp products, diffusion 

 methods of extracting food by-products, and soda recovery from rice- 

 straw liquors. Field work Avith flax, hemp, esparto, and other plants 

 will also be prosecuted. 



STUDIES OF PLANT FIBERS. 



The investigations of plant fibers have been continued in charge of 

 Mr. Lyster II. Dewey, who at the beginning of the fiscal year at- 

 tended the first world congress and exposition devoted exclusively to 

 plant fibers. He presented three papers and took an active part in 

 the discussions. The many different kinds of fiber-producing plants 

 growing on the exposition grounds, the great collections of plant 

 fibers, the fine display of fiber-cleaning machinery in operation, and 

 tlie conferences with men especially interested in fiber-producing 

 plants from all parts of the world aflorded exceptional opportunities 

 for gleaning valuable and accurate information. 



Hard fibers. — About 3.000 bulbils of Af/ave cantala, the most 

 promising fiber agave of Java and the Philippines, have been intro- 

 duced and set out in cooperative trials in Porto Rico and on the 

 Florida Keys. Ileneciuen, sisal, and zapupe plants set out in Porto 

 Rico in former years are growing well, and many of them are now 

 ready to yield their first harvest of leaves. 



70481°— Aoa 1912 27 



