38 Journal of Agricultural Research voi. xviii, no. i 



As shown in Table I, this view was confirmed in every instance where 

 the. acidity had been determined by the ice-water method. For example, 

 with sample i the acidity before bleaching was 18.3, and after bleaching 

 91.8, or five times as high. While less pronounced in samples 2 to 10, 

 the rise in acidity due to sulphuring was distinctly evident in each case. 

 With the Schindler method, as modified by Besley and Baston, the 

 increase in acidity due to sulphuring was hardly, if at all, apparent. 

 In fact, in 5 of the 10 cases the figure for the sulphured sample was even 

 lower than that for the same oats before sulphuring. 



When comparing the results obtained by the two methods on the 

 sulphured samples is, 2s, 3s, and 7s (see Table I), we find that, contrary 

 to the results with unsulphured samples, the alcohol extraction method 

 gave here lower values than the ice-water method. In other words, 

 while practically all the acid of the oat had passed into the ice-water 

 extract in an hour's time, the 18-hour digestion with 80 per cent alcohol 

 had not effected the solution of all acid constituents. Thus, for 

 sample is the ice-water method yielded the acidity figure 91.8; and 

 Besley and Baston's modification of the Schindler method yielded only 

 the figure 55, a deficiency of 40 per cent. While it would not be difficult 

 to offer an explanation for this finding ^ I will confine myself here to a 

 comparison of the values obtained by the two methods. 



From the above experimental results one can not escape the impression 

 that there are a number of objections to the use in work of this kind of 

 the Schindler method as modified by Besley and Baston. Briefly sum- 

 marized, these objections are : 



(i) The lack of a definite endpoint of titration. 



(2) The misleading character of the results obtained by the method, 

 inasmuch as: 



(a) The acidity values of raw, unsulphured cereals arc invariably 

 too high. 



{b) The acidity values for sulphured cereals (oats) are frequently 

 too low. 



(c) The increase in acidity which always occurs when grain is 

 sulphured frequently fails to find expression in the results, the 

 latter quite often indicating instead of the actual increase an apparent 

 decrease in acidity upon sulphuring, due to incomplete extraction 

 of the acid. 

 The above statements refer to results obtained with freshly ground 

 material. It may be mentioned also that for the grain dealer or manu- 

 facturer, as well as for the commercial chemist, the high price of pure 

 alcohol would make this method rather expensive. The cost factor 

 would, of course, be of only secondary importance, provided that the 



' I may only point to the close similarity between this result and the findings of L. Weiss {17), which 

 are discussed in the introduction of this paper. 



