208 EXPERIMENT STATION EECOED. 



According to a summary, the author concludes '• that the available chemical 

 methods are of little value for this purpose. The isolation of putrefaction 

 bases may be attempted, but it is very difficult. The ordinary methods for 

 vegetable alkaloids are useless, as putrefaction bases are almost always in- 

 soluble in ether or chloroform. Special methods, such as precipitation with 

 silico-tungstic acid, may be adopted, but the physiological action is the best 

 test." 



The quantitative estimation of gUadin in flour and gluten, G. A. Olson 

 (Jour. Indus, and Engin. Chem., 5 {1913), No. 11, pp. 9 17-922). ^After review- 

 ing the literature on this topic the author states that the methods which are 

 used for the estimation of proteins in wheat flour are far from satisfactory. 

 The strength of alcohol most suitable for the extraction of gliadin has never 

 been determined. 



"The gliadin nitrogen obtained by the indirect method is much lower than 

 that obtained by the direct method, but agrees remarkably closely with the 

 results obtained for nitrogen in the coagulum in the alcohol-soluble. Of the two 

 methods for the estimation of gliadin, the coagulation method is the shorter 

 and is more sutiable to use for this reason than the indirect method. Alcohols 

 ranging between 50 to 65 per cent, inclusive, by volume extract equivalent 

 amounts of coagulum nitrogen. Above 65 per cent alcohol by volume there is 

 a rapid falling ofE in the amount of coagulum nitrogen obtainable. Alcohol 

 of 50 per cent by volume has been adopted by the writer for the determination 

 of gliadin nitrogen. About 68 per cent of the total alcohol-soluble nitrogen is 

 coagulable. 



"Alcohol-soluble, incoagulable nitrogen is precipitated by phosphotungstic 

 acid. This, together with the coagulable nitrogen, equals the total alcohol- 

 soluble nitrogen. In the same flours as much coagulable nitrogen is obtained 

 in specially prepared gluten as in case of the flour. The easiest and shortest 

 method for the estimation of the gliadin in flour is to estimate the nitrogen in 

 the uncoagulable portion of the alcohol-soluble and deduct this result from the 

 total alcohol-soluble nitrogen." 



The detection of chicory in decoctions of chicoi-y and coffee, C. H. LaWall 

 and L. Fobman (Amer. Jour. Pharm., 85 (1913), Xo. 12, pp. 535-558).— While 

 at present there is no satisfactory specific test for detecting the presence of 

 chicory in roasted coffee, it is possible by inferential tests to note this substance 

 when present. 



"A number of samples of roasted coffee of authentic origin were obtained 

 covering all of the important commercial varieties. In these samples were 

 determined, (1) the amount of extractive, and (2) the percentage of reducing 

 sugars calculated in the extractive previously determined. The amount of ex- 

 tractive matter alone is inconclusive, of course, as no knowledge is usually 

 obtainable concerning the ratio of ground coffee in the decoction." When, 

 however, the ratio of the extractive substances to the reducing sugars present 

 in the decoction is considered, a sharp line of demarcation exists by which it 

 is possible to prove conclusively the presence of 5 per cent of chicory in ground 

 coffee. 



A coffee containing more than 3 per cent of reducing sugars in its ex- 

 tractive matter is looked upon as adulterated with chicory or with a similar 

 product high in reducing sugars. 



The detection of cane sugar in honey, C. H. LaWall (Amer. Jour. Pharm., 

 85 (1913), 2Vo. 8, pp. 376-378). — "It is not possible to detect cane sugar In 

 honey in the sense of a qualitative test. As cane sugar is normally present 

 in small amounts, its quantitative determination, preferably by means of the 

 polariscope, becomes necessary. The form in which sugar is added usually is 



