PHYSIOLOGY: LANGWORTHY AND DEUEL 
515 
It has been a question as to how the milling of Graham flour effects 
its digestibility. Wheat milled by different processes gives bran par- 
ticles varying in size from the very small ones obtained with a burr- 
stone mill to very large ones with a roller mill. The method of milling 
also effects the extent to which the walls of the aleurone cells are broken 
or weakened. These, if intact, prevent the digestion of their contents, 
and so the more they are broken the more completely are the nutrients 
of the flour digested. Lapicque and Liacre^ found that kneading the 
bread broke the aleurone cell walls at points weakened by the milling 
process. Obviously, the method of milling would affect the extent to 
which the walls of the aleurone cells would be weakened. The experi- 
ments here reported were undertaken to determine how different methods 
of milling effected the digestibility of Graham flour. 
The flours were all made from a single lot of Minnesota spring wheat 
secured through the courtesy of the Plant Chemical Laboratory of the 
Bureau of Chemistry. Portions of the wheat were ground by the following 
methods: (1) Small laboratory roller mill, (2) commercial roller mill, 
(3) burr-stone mill, (4) steel-burr mill, (5) steel attrition mill. 
The portions of flour milled on the laboratory roller-mill, the burr- 
stone mill, and the steel-burr mill were prepared on the m lis of the Plant 
Chemical Laboratory, Bureau of Chemistry. The commercial roLer- 
mill flour and the attrition-mill flour were prepared by two commercial 
concerns. 
As was the case in many other tests in this laboratory, the flour was 
fed in the form of a simple 'quick bread,' which was baked each day. 
A little ginger not only added to the palatability but masked any differ- 
ences between the breads in the different tests. The following recipe 
was used: 
1 1 quarts hot water 
The lard was added to the hot water, this mixture was added to the other ingredients. 
This was thoroughly mixed and baked for 1^ hours. 
With a generous portion of the bread a simple basal ration of fruit 
(oranges), butter, and sugar, with coffee or tea without cream, if desired, 
was eaten. The tests were of three days or nine meals duration. The 
separation of the feces, analyses, etc., were those usually followed. 
Experimental bread 
15 cups flour 
3| teaspoons soda 
1| cups molasses 
3f teaspoons salt 
5 teaspoons ginger 
1 scant cup lard 
