4 BULLETIN 1463, U. S. DEPARTMENT OF AGRICULTURE 
this left-over material was added to the part that passed through 
and the whole sample was thoroughly mixed. The mixing was done 
with extreme care to insure that the different types or qualities of 
granulates, of which, no doubt, each sample was composed, would 
be equally distributed throughout the whole sample. This method 
constituted a form of excessive grinding a little different from that 
in method 1, but was for the same purpose. 
(3) The third method of treatment used was that employed by 
LeClere and his coworkers, and was applied to both the coarse mid- 
dlings stocks and the flours. The middlings, because of their rela- 
tive coarseness, were ground once on the smooth rolls, and in one 
case twice before being sifted. ‘This method consisted of the grading 
or sifting out of the particles of various sizes by the use of sieves 
clothed with 8xx, 10xx, 12xx, 16xx, 20xx, and 25xx, silk bolting cloth. 
The purpose of this method was to determine the difference in 
baking quality and chemical composition between different sized 
particles of which flour is normally composed. 
OUTLINE OF CHEMICAL STUDIES 
Each sample resulting from these investigations was subjected to 
the usual flour analyses. The methods used are those described in 
the official and tentative methods of analysis of the Association of 
Official Agricultural Chemists unless otherwise noted. In addition, 
special attention was given to the quality of the gluten in the ex- 
cessively ground samples, as well as to the quantity and quality of 
the gluten in the different-sized flour particles sifted from the 
various flours and middlings stocks. 
The effect of excessive grinding upon the starch particles was also 
studied. The diastatic activity of some of the excessively ground 
flours was determined, as was that of some of the different-sized 
particles of which flour is normally. composed. The diastatic de- 
terminations were also compared with the quantity of total material 
extracted by cold water, as material of this sort was shown by 
Alsberg and Griffing to be composed largely of dispersed starch. 
The data showing the chemical composition of the two series of 
flour samples excessively ground in the way previously described as 
methods 1 and 2, are given in Tables 1 and 2. The chemical com- 
position of flour particles, or granulates, of varying degree of fine- 
ness, of which middlings stocks ground to a normal degree of fine- 
ness and commercial flours are composed, is given in Table 3. 
