PRACTICE XXIII 



DETERMINATION OF NITROGEN IN ANIMAL EXCREMENTS, 



SOLID AND LIQUID 



Each group of students will work upon one of the following : J 



1. Horse excrements. 6. Poultry excrement and fresh 



2. Steer excrements. cow's milk. 



3. Cow excrements. 7. Human excrements. 



4. Sheep excrements. 8. Wheat straw and manger ref- 



5. Swine excrements. use (for bedding). 



Kecord age and condition of animals and food rations as nearly 

 as possible in all cases. 



For solid excrement : Weigh out 10 g. of fresh substance on filter 

 paper, placed on a watch glass, and transfer both paper and excre- 

 ment to a Kjeldahl flask. 



For liquid excrement : Measure out 10 cc. and place in a Kjeldahl 

 flask. Compute weight from specific gravity g. 



Solid Liquid 



Titrations (1) cc. XH 3 



(2) cc. XH 3 



Av. cc. X H 3 



Per cent X 



Calculate the results obtained, and with these record the results 

 obtained by three members of each group, as indicated upon the 

 following page. Value nitrogen at 15 cents per pound. 



10 tons alfalfa hay contain Ib. X 



1 ton fresh cow dung contains Ib. X 



How many tons of fresh cow dung would be required to furnish 

 nitrogen for 10 tons of alfalfa hay ? 



1 The student is encouraged to add to the required materials some other substance 

 which may be of possible importance in his home community, including especially 

 any organic refuse occurring in consequential amounts. 



