AGRICULTURAL EXPERIMENT STATION. 



17 



Experiment stations have assumed that the organic nitrogen of mixed 

 fertilizers is supplied in the best forms, and have valued it accordingly, 

 but it has been recognized, at the same time, that some way of detecting 

 inferior forms is extremely desirable. The method for doing this which 

 has received most attention, is based upon the different degrees of solu- 

 bility of organic nitrogen compounds in a pepsin solution. The nitro- 

 gen of dried blood, dried flesh, cotton-seed meal and similar high grade 

 nitrogenous materials, is very largely dissolved by digestion in a pepsin 

 solution, while that of horn, hoof and leather is much less affected by 

 this treatment. 



In support of this statement, there is given below the results of ex- 

 periments conducted in three different laboratories for the purpose of 

 testing the value of this method. With regard to most of the materials 

 used, these results are practically in accord. 



Solubility op Certain Nitrogenous Materials in Pepsin Solution. 



Materials Used. 



Per Cent, of Total Nitrogen 

 Dissolved as found by 



Shepard Conn. i Maine 



& Chazal. Expt. St&. | Expt. Sia. 



Dried Blood 



Cotton Seed Meal... 



Ground Bone 



Dried Flesh 



Dried Fish 



Fish Scrap 



Tankage 



Wool Waste 



Leather 



Horn and Hoof Meal 



99-8 

 78.6 



83.2 

 85-7 

 83-1 



93.3 



88. G 

 84. 



61.3 



37-8 



98.2 



84-0 



86. G 



96.8 

 97.9 



92.7 



97.3 



52. to 99.* 

 av. 78. 



80.5 



58. to 72. t 

 av. 66- 



4.8 



25.4") 

 35.1) V34.9 



33.3 J 



7.2) 



22.4 H9.3 

 28.2 J 



97-3] 

 93.3 i 

 97. G 

 95. X) 



J.3 



95.8 



75.71 

 75.4 V 76. 5 



78. 4j 



58.0 



48-6 



53.3 



1:?{»- 



25.6 



20 samples. t 7 samples. 



