20 



Journal of Agricultural Research voi. xviii, no. 



Since BrowTie {4) and Maxwell (/j) have recommended and used the 

 ratio of protein to nonprotein nitrogen in cane juice as an indication of 

 the stage of maturity of the plant, these determinations were made on 

 sorghum juice by means of Stutzer's reagent {20, p. 38). The results for 

 50-CC. samples follow : 



Sample i. 

 Sample 2. 



Percentage of 



nitrogen in 



juice. 



O. 0204 

 . 0191 



Percentage of total nitrogen 



Albuminoid 

 nitrogen. 



39-2 

 35-8 



Amid nitrogen. 



60.8 

 64. 2 



In sugar-cane juices the albuminoid nitrogen may vary from 20 to 70 

 per cent of the total nitrogen, depending upon the age of the juice and 

 the method of extracting the juice. The high proportion of "amid 

 nitrogen" in sorghum is significant from the viewpoint of sirup manu- 

 facture since it represents the impurities which are not coagulated by 

 heat and which are not in large part removed by lime defecation. They 

 no doubt contribute to the flavor of the sirup. 



It was found that lead acetate, lead subacetate, and mercuric nitrate 

 would each precipitate a different amount of material from the juice. 

 Therefore these reagents were used to remove fractionally the nonsugar 

 solids from the juice. The mercuric nitrate was added to the filtrate 

 from the lead acetate precipitate and the lead subacetate brought 

 down the third fraction. The following are the data for a typical 

 example of this precipitation on a juice containing 0.0265 P^^ cent of 

 nitrogen : 



Thus, three-fourths of the nitrogen can be removed by these precipi- 

 tants. 



Forty-eight liters of juice w^ere treated in this way, the precipitates 

 being separated and washed by centrifuging. The precipitates were 

 decomposed with hydrogen sulphid, the metallic sulphid filtered off, and 

 the filtrate concentrated in vacuo at 30° C. to a thin sirup. From all 



