208 



AGRICULTURAL EXPERIMENT STATION. 



Determination I .. 



" ir. 



" III 



Milligrams. 

 Cu calculated from 

 CuO. 



.0718 



.379 



.375 



Starch. 



The five grams that have been leached for sugars are washed 

 into a flask with 150 c. c. water, the flask attached to a condenser 

 to prevent the escape of steam and the contents boiled for one-half 

 hour. Then fifty c. c. of a two per cent solution of HCl are added 

 and the boiling continued for one-half hour more, the solution 

 filtered through linen into a beaker and the residue thoroughly 

 washed with hot water. (The washing is much facilitated b\' wring- 

 ing the water completely out each time before adding a new portion). 

 The beaker is then placed on a steam bath, the solution evaporated 

 to nearly 200 c. c. and 15 c. c. HCl (Spc. grav. 1.12) added and the 

 heating continued for three hours. The solution is then filtered if 

 necessary, transferred to a 250 c. c. flask, made slighily alkaline 

 with KHO, filled to the mark and filtered through dry filter. 

 Twenty-five c. c. are taken for each determination. 



The above method was employed for the determination of starch 

 in some coarse fodders and excrements where it was thought desira- 

 ble to use a method that was compatible with our present one for 

 determination of crude fibre. Most of the methods published here- 

 tofore subject the fodder to the direct action of the acid for the 

 time required to convert the starch to sugar. 



Such treatment will give a much larger percentage of starch than 

 is found in the acid solution from a crude fibre determination, and 

 will also reduce the total amount of fibre in about the same propor- 

 tion. A few comparative tests were made with the method recently 

 published by Mr. E. F. Ladd,* in which the fodder is treated with 

 150 c. c. water containing four to five c. c. concentrated HCl for 

 twelve hours at 100° C. 



A sample of Timoth}' treated by this method gave about seven 

 per cent more starch than the method described above, and to ascer- 

 tain whether the cellulose was very much acted on, a crude fibre 

 determination was made, treating the fodder with 200 c. c. water 



*Sixih Annual Report N. Y. Agricultural Experiment Station, p. 462. 



