78 HATCH EXPERIMENT STATION. [Jan. 



2. The Digestibility of Galactan. 



REPORTED BY J. B. LINDSEY.l 



Those carbohydrates that can be removed from plants and 

 seeds by the action of dikite mineral acid and alkali, and 

 that are soluble in F. Schulze's reagent, E. Schulze has 

 termed hemi-celluloses. Under this headine" he has brought 

 the mother substances, — dextran, levulan, mannan, galactan, 

 araban and xylan ; which yield on inversion the sugars, — 

 dextrose, levulose, mannose, gaUctose, arabinosc and xylose. 

 These hemi-celluloses are intermixed with the true celluloses 

 in the cell walls of the plants and seeds. They have been 

 frequently recognized as reserve material, being used by the 

 embryo during the S})routing of the seed. The levulan and 

 mannan have not been found generally distributed, while 

 the araban and xylan (pentosans) constitute fully one-third 

 of the extract matter of all hays and straws, are quite prom- 

 inent in the hull and bran of most grain seeds, and are even 

 found in the endosperm and cotyledons of many seeds. 



Galactan was first extracted from lucerne seeds by Muntz,^ 

 and was converted into galactose by boiling with dilute acid. 

 E. Schulze ^ and his co-workers found considerable galactan 

 in the seeds of the blue lupine, and as a result assumed that 

 this hemi-cellulose might be very generally distributed in 

 agricultural plants. Lindsey and Holland '* determined the 



1 This experiment was carried out by Mr. E. S. Fulton of the class of 1904 of the Mas- 

 sachusetts Agricultural College, who expressed a desire to undertake work of this 

 character for a graduation thesis. The sheep and apparatus belonging to the depart- 

 ment of foods and feeding were placed at his disposal. The digestibility of the hay 

 used had already been determined. Mr. Fulton assumed charge of the sheep, and pre- 

 pared the f.Tces for analysis in the station laboratorj^. The analytical work was done 

 atthecollege laboratory, under the supervision of Prof. C. Wellington. INIr. Fulton ex- 

 presses his thanks to l^rofessor Wellington and also to Dr. Lindsey and his co-workers 

 for the many lioljjs and suggestions received. 



2 Bui. Soc. Clieni. (2), .37, p. 409. 



s Zeitsch. f. physiol. Chem. T.d. 14, Heft. .3, Zeitsch. f. physiol. Chem. Bd. 16, Hefts. 4 

 and .5. 

 ♦ Ninth report of tlie Uatcli Experiment Station, pp. 92 -96. 



