180 EXPERIMENT STATION RECORD. 



The United States Department of Agriculture and silk culture, L. O. Howard 

 ( U. S. Dept. Agr. Yearbook 1903, pp. 137-148, ph. 5). — A historical statement is given 

 of the various efforts which have been made in this country to establish the raising 

 of silk worms upon a profitable basis. The present work of the Department along 

 this line began July 1, 1902, and has involved an inspection of methods of silk rais- 

 ing in southern Europe, the purchase of cocoons by the Department, and experi- 

 ments in reeling silk. 



The outlook for a natural market for cocoons in this country is considered problem- 

 atical but rather hopeful. In order to show the economic importance of raising 

 our own raw silk, statistical data are presented concerning the importation of raw 

 silk during the years 1892 to 1902. 



FOODS— NUTRITION. 



Entire wheat flour, C. D. Woods and L. H. Merrill (Maine Sta. Bid. 103, pp. 

 61-76, j>!. 1). — The results of studies upon the milling of wheat, chemical composi- 

 tion, digestibility, and nutritive value of so-called entire wheat, Graham, ami ordinary 

 flours are summarized and discussed. The fact is pointed out that the introduction 

 of the roller process of milling has made it possible to utilize hard spring wheats rich 

 in gluten and to include in the straight or standard patent flour a considerable por- 

 tion of the grain which in the old process of milling was lost in bran and middlings. 

 It is noted that "this has materially improved the bread flours in common use until 

 the standard flours from hard wheat carry more protein than almost any Graham 

 flour in the market 25 years ago, and as much or more than many Graham flours 

 now on the market. Furthermore, the demand for bread flour of high gluten 

 content has stimulated wheat breeding and the growing of hard wheat, so that even 

 winter wheats are now grown which in gluten content rival the hard spring wheats 

 of the Northwest." 



Analyses of cleaned wheat and bran from entire-wheat flour and from straight-grade 

 flour are reported. These analyses and microscopical studies showed that the brans 

 from the 2 sorts of flour were "as nearly identical as 2 brans from the same kind of 

 milling and the same wheat would be likely to run." 



According to the authors' calculations 100 lbs. of cleaned wheat will, with modern 

 methods of milling, yield very nearly 100 lbs. of Graham flour, about 85 lbs. of 

 entire-wheat flour with 15 lbs. of bran, or about 72 lbs. of straight or patent flours 

 with 13 lbs. middlings and low-grade flour and 15 lbs. bran. In other words, the 

 entire-wheat flour and the standard patent flour differ from each other only in that 

 the former contains the middlings and low-grade flour, the bran being omitted from 

 both. 



"It therefore follows that whatever of nutritive value there is in entire-wheat flour 

 that is lacking in patent flour must be sought for in the middlings and low-grade 

 flours. These materials are usually higher in protein content than the straight flour. 

 The protein of the most importance in wheat flours is in the form of gluten. The 

 gluten of second clear flour is of poor quality and on this account this grade of flour 

 makes a heavy loaf. The red-dog flour is obtained from the germ or embryo and 

 adjacent parts of the kernel. While usually high in protein, it is dark in color, and 

 because of the poor quality of its gluten has little expansive power and makes a very 

 inferior loaf. The middlings contain much of the germ, the aleurone layer of the 

 bran, and finely ground particles of the outer coatings. It is usually high in protein 

 content, but with practically no gluten. 



"It is probable that much of the laxative qualities noticed in Graham flour and 

 which Lawes and Gilbert attributed to the coarse particles of bran, are in reality due 

 to the character of the protein and mineral compounds of the aleurone layer and the 

 germ. For while entire-wheat flour is not so much of a laxative as Graham, it pos- 



