84 



BULLETIN 



U. S. DEPARTMENT OF AGRICULTURE. 



tive work that the nesslerization method caused difficulty, although 

 the reagents used were the same as those which had given satisfactory 

 results a few months before. He considers the method too uncertain 

 on account of the foaming and sometimes also turbidity to meet with 

 general approval. 



The consensus of opinion of those who participated in the work 

 here reported is that while the nesslerization method for ammonia 

 nitrogen in frozen-egg products may, because of the shorter time 

 which it consumes, be of value, it is not nearly as accurate as the 

 titration method, which is preferable where absolutely dependable 

 results are required, as, for example, in analyses where court action 

 may be involved. If the nesslerization method is used for this purpose 

 it should be run in triplicate and the average result employed. 



Strength of Alumina Cream to Be Used in the Reducing Sugar Determi- 

 nation. 



During the course of the work the question arose as to whether, 

 if alumina cream was kept in a large container and was not always 

 shaken to a homogeneous mixture before a portion was removed 

 for use, the results would be affected by the use of cream of varying 

 concentrations. To decide this, alumina cream of regular strength 

 was prepared, and it was used as such and also after dilution with 

 varying amounts of water. The results are shown in Table 37. 



Table 37. — Reducing sugar obtained with alumina cream of varying strengths. 



Initial of analyst. 



100 ec. 



alumina 



cream, 



Occ. 



water. 



75 CC. 



alumina 



cream, 



25 cc. 



water. 



50 CC. 

 alumina 

 cream, 

 50 cc. 

 water. 



25 cc. - 

 alumina 

 cream, 



75 cc. 



water. 



B 



Per cent. 

 0.31 

 .31 

 .38 

 .36 

 .33 

 .16 

 .43 

 .35 

 .32 



Percent. 



0.30 



.30 



.36 



.36 



Per cent. 



0.30 



.31 



.37 

 .38 

 .32 

 .18 

 .44 

 .34 

 .34 



Per cent. 

 0.29 



B 



.32 



D 



.37 



D 



.36 



E 





E 







E 







H 



.36 

 .33 





S..„.. 



.32 







These tabulated results prove conclusively that the concentration 

 of the alumina cream has no influence. 



Choice Between Sulphuric and Htdrochloric Acids in the Detection op 



Indol and Skatol. 



Experiments proved that sulphuric acid is preferable, because it 

 gives more distinct colorations. 



