42 Journal of Agricultural Research voi. x\tg[i, No. i 



and the acidity values found are listed under No. i8sr and 2isr, respec- 

 tively. It is noticeable that these sulphured samples showed no increase 

 in the ice-water acidity even though they had stood for a prolonged 

 period after being ground. It would seem, therefore, that the increased 

 titration values found in these instances with the Schindler method are 

 wholly due to the formation, on standing, of amphoteric protein deteri- 

 oration products. The latter are not determined by the ice-water 

 method, since by its use only substances are measurable which react 

 acid in aqueous solution. In other words, the interesting fact is appar- 

 ent from these results that with ground samples which prior to the 

 grinding have been sulphur bleached the ice-water acidity does not 

 increase on standing, while unsulphured oats with the same method 

 and under like conditions always show an increase in acidity. The 

 sulphur bleaching, therefore, has probably destroyed the acid-forming 

 ferments of the grain. It has not, however, stopped the decomposition 

 of the proteins, and the rate of this decomposition is doubtless registered 

 by the increased titration values obtained for these samples when 

 Schindler's method is used. The latter method might, therefore, under 

 certain conditions and when used in conjunction with a true acidity 

 method, be developed into a useful measure for the rate of decomposi- 

 tion of proteins, as already pointed out in my previous paper. 



The barley samples and many of the oats samples listed in Table II 

 had been collected by me at various grain elevators in the Cen- 

 tral West during the fall of 191 6. The five samples of commercial 

 com meal No. 53 to 57 had been examined by me seven months pre- 

 viously by means of the ice-water method. The values then obtained 

 are recorded in parenthesis for comparison. These corn meal samples 

 were extracted with ice water for iK hours, as against i hour for bar- 

 ley and oats. The figures in Table II represent cubic centimeters of 

 normal alkali which were required to neutralize the extract from 1,000 

 gm. of the material. The moisture content of the latter was not taken 

 into account. The determinations were made in the laboratory, using 

 an ice-water bath, in the manner described under the next heading. 



The values obtained by the two methods in the extraction of the corn 

 meals 53 to 57, which had been purchased in the open market, are also 

 of interest.* The ice-water values of Mr. Mastin, compared with those 

 which I had obtained seven months previously (the latter being shown 

 in parenthesis) indicate a distinct rise in acidity for the whole kernel 

 meals 53 to 55 but no rise for the degerminated meals 56 and 57. Pos- 

 sibly the latter meals had received some kind of chemical treatment 

 which prevented the increase in acidity in a similar manner as the sulphur 

 bleaching had prevented it in the oat samples i8sr and 2isr. Another 

 explanation would be that the acid-forming ferments are all located in 

 the germs and had been removed with the latter. Unfortunately I had 



* The yellow corn meals 53 to 55 had been reground to about the same fineness as samples 56 and 57. 



