EXPERIMENT STATION BULLETINS. 



513 



During the progress of the experiment daily analyses were made of the urine 

 and feces of each animal and at the end of each period the results were averaged, 

 giving the data for that particular period and feed. The urine of each animal 

 was kept by itself in a large glass jar and a composite sample made daily at the 

 same hour. Some difficulty was experienced in getting an average sample of the 

 feces, until the happy idea suggested itself of using an earthen jar, adding water 

 and mixing the contents with a hoe until it was thoroughly uniform. The samples 

 duplicated nicely by this procedure, showing accuracy of mixing. 



The results were measured in the laboratory by estimating the total nitrogen 

 in the natural feces, dried feces, and in the feces after treatment to remove 

 nitrogneous products of metabolism. The determinations were, in all cases, made 

 in duplicate and sometimes in triplicate. The natural feces or the wet samples 

 were analyzed immediately after being brought to the laboratory in sealed glass 

 jars. The dried feces were analyzed, after carefully drying in an electric oven 

 below 70 deg. C. In no instance during the whole experiment did there fail to be 

 an appreciable loss of nitrogen in drying. The nitrogen-products of metabolism 

 were sepai-ated by the ether, alcohol, water and lime water method,' and the 

 nitrogen determined in the residue, which was assumed to represent the undi- 

 gested food. 



FIRST EXPERIMENT. TERIOD ONE. 



Feed given, 7 . 5 pounds oat straw, 2 . 5 pounds clover hay, 1 pound bran, 1 pound corn and cob meal. 

 Total dry matter, 10.65 pounds per day per cow. 

 Nutritive ratio 1 to 12.2. 



Grams op Nitrogen in 

 Cow 1. Cow 2. 



1 This method was conducted as follows: — 1 gram of the dry, finely ground feces was treated with 25 cc. ether and 

 boiled in an Erlenmeyer flask for i hour with a reflex condenser. The solution was then decanted on a 9 c. m. filter and the 

 process repeated with a final washing by decantation until the feces gave no color to the ether. 50 cc, 95% alcoliol is 

 now poured upon the residue in the flask and boiled for 10 minutes as before. The supernatant fluid is now decanted upon 

 the same filtei as was used for the ether and the product washed with liot alcohol The sample is then treated on the steam 

 bath for 20 minutes with 50 cc. water and the whole transferred to tlie same filter as before and washed thoroughly with hot 

 water. Filter and feces are next transferred to a beaker with 50 cc. of a saturated solution of lime water and allowed to 

 stand over night or for at least six hours. The whole is tlien transferred to a fresh filter and thoroughly washed with 

 diluted lime water. The filter and contents are then dried and the nitrogen determined in the usual way. 



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