COMMERCIAL FEEDING-STUFFS 247 



than the flour, one-third richer in protein, with corres- 

 pondingly less starch. "Graham" flour, which contains 

 more or less of those parts which pass into the offal in 

 milling white flour, does not differ so much from the 

 whole kernel. Middlings differ from bran in containing 

 less of the hard, tough coatings and more of the finer 

 parts of the kernels, and this feeding-stuff varies from 

 the coarser kinds to the fancy middlings, according to 

 the proportion of starchy material present. Red Dog 

 flour is counted among the offals from milling wheat, and 

 it represents the dividing line between the middlings and 

 the high-grade flour. 



335. Milling processes compared. There is a belief 

 more or less prevalent that bran from the old milling 

 processes which contained more of the starchy part of 

 the kernel than is now the case, was more valuable than 

 roller process bran is. It is probable that a greater pro- 

 portion of starch increases the digestibility of bran, and 

 in this sense the old process bran was superior to the 

 roller process product; but, on the other hand, the latter 

 is more nitrogenous than 'the former and is therefore 

 more efficient as a protein supplement to home-raised 

 foods. 



336. Screenings. Wheat, when sold to the mills, con- 

 tains besides inferior wheat grains a certain percentage 

 of foreign materials such as other grains, weed seeds, 

 chaff, bits of straw, and even particles of grit. Before the 

 wheat is milled these materials are removed and in com- 

 merce are known as screenings. While the percentage 

 of this foreign matter in wheat is small, the aggregate 

 quantity of this offal put on the market is very large. 

 Screenings contain ingredients of greatly varying qual- 

 ity, some of which are very inferior. This offal is almost 



