16 BULLETIN 839, U. S. DEPARTMENT OF AGRICULTURE. 
It is interesting to observe the variety of streams drawn upon for 
the composition of different so-called patents, as well as the varia- 
tion in the offal count of the stocks employed in the milling of such 
finished flours. If space permitted, additional information could 
be submitted to illustrate how variable the different mill stocks are 
as far as offal content is concerned. In many instances where 
lower-grade stocks have been employed in making a flour, however, 
the finished product has usually been purified sufficiently to cause 
the resultant offal count to be appreciably low. And in many cases 
the contrary is true. 
EXAMINATION OF COMMERCIAL GRADES OF FLOUR. 
The assembled flours employed in this part of the investigation 
were collected by B. C. Winslow, food and drug inspector, Bureau 
of Chemistry, United States Department of Agriculture. As these 
flours were milled under a variety of conditions, they necessarily 
reflect such conditions in the finished product. The inspector gave 
the following statement as to the designations applied to these 
flours: "As a general thing, these names were used in harmony 
with the usage of the mill where they were taken. The method of 
assembling, with the streams, percentages, etc., were given when 
feasible, and as correctly as possible from the information available. 
The general terms ' patent/ ' clear/ and ' straight' were used to clas- 
sify in a general way the assembled grades of flour, and vary with 
each mill." 
With this information in mind, an attempt was made to apply the 
microscopical method already described to an examination of these 
products for the purpose of developing a system for the classification 
of flours based on the offal content. A detailed discussion of the 
actual data obtained from these tests, with a general summary on the 
various so-called grades, follows. 
PATENT FLOURS. 
PATENT FLOURS MILLED PROM HARD WHEATS. 
Thirty-six patent flours said to have been milled from hard wheats 
were examined microscopically, and their bran particle and hair 
count determined. The commercial grade designations ranged from 
40 to 94 per cent. In some instances the flour had been bleached; 
in others it was bleached only lightly or not at all. Table 16 gives 
the results of this examination. 
