165 



<>rn by evaporating the steep water after careful treatment to a thick sirup, which 

 contains these substances partly in solution and partly in suspension. This sirup 

 is added to the feed, which latter forms an ideal absorbent. 



An analysis of gluten feed thus prepared has the following average composition: 



Per cent. 

 \\atcr 10 36 



I'rotoin 25.95 



I''" 1 2.18 



Starch ... 18. 09 



I'ilx-r 6. 50 



A-h 3.70 



Nitrogen-free substance (by difference) 33. 22 



Soluble i approximate) 15. 50 



From the process outlined above it is obvious that no extraneous matter is intro- 

 duced into the feed and that the ingredients which go to make up the feed occur there 

 in the same form as in the corn itself, although, of course, in a more concentrated 

 form. It was not without surprise, therefore, that I noticed in a number of analyses 

 published recently a reference to an "acidity" of the feed, which was reported as 

 hydrochloric acid. It is not quite plain why the acidity was expressed in such a 

 manner, as no hydrochloric acid, or for that matter any other mineral acid, is present, 

 none having been introduced at any stage of the process of manufacture. It cer- 

 tainly would not occur to anyone to report the acidity in fruits, vegetables, cider, 

 or u in. - as hydrochloric acid, no more than in the case of wheat flour patent flour 

 in which the aridity runs nearly as high as some of the acidities reported in gluten 

 fei-d-. I am not prepared to -tate at this moment with any degree of finality whether 

 thi- appnreni aridity i- due to acid salts, such as the organic phosphorus compounds, 

 or to the presence of a slight amount of lactic acid, or to proteid bodies, such as the 

 acid albumins; but, whatever causes it may be due to, if the absence of free mineral 

 a il- has been proved, it should be reported as an organic acid, preferably lactic. 

 It might perhap- be -till better in state the number of cubic centimeters of normal 

 alkali rei|iiiri-d to neutral: 



In this connection it i- of import to note the varying results obtained in acidity 

 determination.-, depending upon the character of the indicator employed. To cite 

 an instance, we have found that phenolphthalein causes the acidity to appear two to 

 three timi - higher than rosolic acid. Again, when methyl orange is used, an alka- 

 linity is indicated. The-e discrepancies and variations make it desirable in fact, 

 -ary ihat the othcial methods governing the analyses of feeding stuffs provide 

 i u lard indicator for such acidity; means should also be provided for expressing 

 properly such acidity as may be found in the feed. 



If, as a safeguard, it is deemed advisable to test for free mineral acid, Toepfer's 



limethylamidoazobenzol), or the even more delicate Giinzburg test (phloro- 



glucin), are to be recommende. 1 . These tests are generally employed in physiological 



research and reveal the slightest traces of free mineral acids in the presence of organic 



arid-. 



A great desideratum in gluten feed is uniformity; that is, the feed made at the dif- 

 ferent fa< tories located in different sections of the country should be uniform in 

 composition as well as in appearance. So far as the first is concerned, the variation 

 is very slight . the processes employed in our various factories being under such control 

 as to insure practically uniform composition, irrespective of point of manufacture. 



The appearance of the feed is of considerable moment. In former years the corn 

 delivered to our factories was mostly of the yellow type, the amount of white corn 

 delivered I- in- rather insignificant. During the past four years, however, the situa- 



Contains 17.18 per cent pentosans. 



