346 PROCEEDINGS OF SECTION B. 



Determination of Water Soluble Constituents. — From the determina- 

 tion of extractives, which are considered the most rapidly assimilable 

 portion of a feeding stuff, we would form some estimate of its palatability 

 and stimulating properties. To obtain an aqueous extract, we adhere 

 to the following procedure : — Twenty grms. of the sample are allowed 

 to stand with 50-100 ccs. water overnight. A few drops of chloro- 

 form may be added to prevent fermentation. Shake frequently, decant 

 off, repeat operation, adding water, and decant again. Finally digest 

 in water bath for one hour, and after cooling add to previous 

 extracts, making up to 500 ce. Determine in aliquot parts — (1) total 

 soluble matters ; (2) total soluble ash ; (3) soluble nitrogen ; (4) soluble 

 carbohydrates after inversion. 



In the case of very starchy substances the digestion may be omitted, 

 as it is difficult in this way to obtain a clear solution. Extraction of 

 the soluble carbohydrates of two samples of grass — Astrebla pectinata 

 and Panicum juhiflorum — with alcohol and water gave the following 

 results : — 



Astrebla pectinata, Panicwn jubiflorum. 



Invert sugar ,,, „ 2*95 per cent. .■ 2 -57 per cent. 



Cane sugar r4:2 " , 1"41 " 



Dextrin 1-25 " (cont. soluble starch) 1*09 " 



Total 5-62 per cent. 5"07 per cent. 



Determined in the usual way, as above, and calculated as dextrose, 

 water soluble carbohydrates amounted respectively to 6'41 and 6*00 

 per cent. 



The Undetermined Residue in the analyses in table I. amounts to 

 between 2*96 and 15"62 per cent., and is considered as made up of amide 

 bodies, chlorophyll, undetermined extractives, as tannin, and carbo- 

 hydrates of an intermediate nature and akin to cellulose. These are 

 not included in pentosan or provisional starch determinations, nor 

 contained in the crude fibre of Konig. The amount of these substances 

 may be roughly gauged by subtracting the undetermined portion of the 

 water soluble extract from the total undetermined matter, and would 

 appear to vary widely in plant substances. 



We have felt that the difficulty attendant upon all elaborate 

 schemes of fodder analysis has been in the practical interpretation of 

 results. This has arisen from the as yet imperfect knowledge possessed 

 as to the physiological action and nutritive properties of the substances 

 determined. 



In this laboratory in the evaluation of fodder materi^als from their 

 analyses special regard is had to the percentages of true protein, total 

 water soluble material, soluble protein, soluble carbohydrates, starch, 

 and to the low content of crude fibre. 



In the present state of our knowledge we would place the feeding 

 value of the constituent carbohydrates of feeding stuffs in the order — 

 soluble carbohydrates, starch, pentosans, undetermined carbohydrates, 

 and crude fibre. 



