ANNUAL REPORT, 1944-45 25 



The Chemical Investigations of Hemicelluloses. (Emmett Bennett.) Hemi- 

 celluloses were isolated from corncobs and rye straw by the alkali method. Hypo- 

 chlorites and bromine were used in purifications. The purified substances were 

 subjected to chemical treatment which would indicate some facts regarding their 

 chemical nature. The results of these investigations seem to indicate the follow- 

 ing: 



(a) Xylose appears to be the chief sugar present in both preparations. A 

 uronic acid, believed to be glucuronic acid, was also present in both samples. 

 Glucose was present but galactose could not be detected. 



(b) As indicated by acetylations, corncob hemicellulose has two free hydroxyl 

 groups. The theoretical acetyl content of C9H12O6 is 39.81 percent; the pre- 

 pared product contained 39.73 percent. The theoretical and actual carbon con- 

 tent of the acetate are 49.98 and 49.50 percent respectively. These data indicate 

 that the xylose units probably are linked through the 1, 4 positions and that the 

 preparation was quite pure. Hemicellulose from rye straw does not acetylate 

 satisfactorily. 



(c) The "repeating units" appear to be of from 25 to 40 units in length, cor- 

 responding to an approximate molecular weight of from 3000-6000. 



(d) Hydrolytic and polariscopic studies indicate that the xylose units in 

 both hemicelluloses have a pyranose structure with a beta-type linkage between 

 units. 



(e) Alkali-lability numbers are about equal and are comparable to those of 

 commercial samples of corn starch. 



(f) Complete hydrolysis of both hemicelluloses could be obtained with 4 

 percent sulfuric acid in approximately four hours, whereas the usual time is about 

 15 hours. This shorter time of hydrolysis decreases the destruction of uronic 

 acids. 



The Investigation of Agricultural Waste Products. — 1, The Chemical Investiga- 

 tion of Lignin. (Emmett Bennett.) The work on this project to date has been 

 devoted to ascertaining the effect of large quantities of pure lignin upon the 

 aerobic decomposition of plant materials of varying composition. 



Pure lignin was added to finely ground samples of silage, timothy hay, corn 

 stalks, and oat hay, thoroughly mixed, inoculated with a soil suspension, and 

 allowed to incubate at about 32°C. for several months. The lignin contained 64.2 

 percent of carbon and 5.6 percent of hydrogen and was added in amounts equiv- 

 alent to about 14 percent of the plant material. In order to increase the supply 

 of nitrogen for microbial activity one gram of nitrogen in the form of ammonium 

 carbonate was added to each 100 grams of organic material. Controls were used 

 in each case. At definite intervals, representative samples were removed and 

 analyzed for total nitrogen, ammoniacal nitrogen, solids, and pH. 



Tentati\^e results indicate that there was a greater loss of organic matter from 

 the corn stalks and oat hay in the presence of added lignin: timothy hay and 

 silage decomposed at about the same rate with or without lignin. In general, 

 ammonification was retarded in the presence of lignin. 



Although we have no data on the influence of the products of decomposition 

 on the vigor of the plant, it would seem that added lignin does not materially 

 alter the rate of the aerobic decomposition of plant material if sufficient nitrogen 

 is available. 



Factors Affecting the Vitamin Content of Milk and Milk Products. (Arthur D. 

 Holmes.) Milk, which has been described as nature's most perfect food, is of 

 especial importance to the residents of Massachusetts. From the farmers' view- 

 point, it is one of the principal agricultural products of the State and it is highly 



