416 



Scientific Proceedings (131) 



There are a few instances of considerable rise, far beyond any 

 experimental error. Although these occur only in those cases 

 where inorganic salts were present and can probably be ex- 

 plained on the grounds that these were not entirely removed, 

 the facts are not without interest. Using CdCl 2 in an attempt 

 to remove lecithin, the filtrate of No. 93.2 showed a rise of 339 

 mg. against an original drop of 96 mg. The precipitate thrown 

 down by (NH 4 ) 2 S0 4 in No. 108x showed a rise of 79 mg. 

 against an original drop of 69. 



There are other instances where a slight rise was consistently 

 found, but being within the limits of experimental error the 

 results may not be significant. This is noticed especially in the 

 case of the precipitate thrown down by alcohol and in the fil- 

 trates, when inorganic reagents are used even though dialyzed 

 and though the evaporated solution shows no microscopic evi- 

 dence of the crystals of the substance used. 



A series of experiments was conducted with acetone as a 

 precipitant' with three equivalent portions of varying acidity, 

 one made slightly acid, the second practically neutral and the 

 third slightly alkaline. In those results which gave positive tests 

 there was a very marked gradation first in the potency and sec- 

 ond in the nitrogen content. The most acid of the three yields 

 the most potent precipitate and has the lowest nitrogen value. 



TABLE II. 



EFFECT OF REACTION ON PRECIPITATION BY ACETONE 



Extract 





Reaction 



Original 





Potency 



Nitrogen 



Number 



Precipitant 



or Ph 



Potency 





of ppt. 



% 







slightly 



—.090 









98-2 



Acetone 



acid 





—.039 





98-2 



< < 



neutral 

 slightly 



—.090 





—.039 





98-2 



< t 



alkaline 



—.090 





—.023 

 —.094 



6.54 



99-2A 



1 1 



5.8 



— .008 





—.071 

 k —.030 



4.26 



99-2A 



< t 



6.7 



—.063 





—.023 

 —.041 



4.92 



99-2A 



( i 



8.8 



—.063 





—.053 

 ' +.007 



6.08 



1*3-1 



< < 



5.7 



—.046 





—.008 

 * +.004 



10.3 



103-1 





6.7 



—.046 





—.003 



; +.015 



10.2 



103-1 



« < 



7.8 



—.046 



■ 



—.028 



M.O 



