366 EXPERIMENT STATION EECOED. 



In artificial digestion experiments it was found that overbleaclied flours 

 underwent a slijj;litly fj;reater degree of tryptic digestion tlian inibleached flour. 



" It may be concluded from these results that the bleaching of flour does not 

 in any degree diminish the readiness with which it undergoes tryptic digestion 

 in vitro." 



As regards peptic digestion, the author's results " show a decided, although 

 small, inhibition in the digestion of the bleached samples, the numbers given 

 by these in 4 hours being decidedly less than those of the unbleached. At the 

 expiration of 22 hours this difference had disappeared." 



The author's experiments, which have to do .with the rapidity of digestion, 

 confirm the observation that " the gluten of unbleached flour is much the more 

 rai)idly dissolved. ... In view of the results obtained with flour with which 

 the rates of solution are only slightly different, it would seem that the effect 

 is due rather to some change produced in the physical properties of the gluten 

 obtainable from the flour than to the formation of a less readily digested 

 compound." 



Experiments were also made in which overbleached flour and aqueous extracts 

 of grossly overbleached flour and of commercially bleached flour were ad- 

 ministered to small animals (rabbits and a cat). 



The results showed that " the extract from commercially bleached flour, from 

 overbleached flour, and even that from grossly overbleached flour is apparently 

 harmless to animals under the above conditions." 



A list of references follows the paper, and a quotation in full of U. S. Depart- 

 ment of Agriculture Food Inspection Decision No. 100 (E. S. R., 20, p. 863). 



On the bleaching of flour and the addition of so-called " improvers " to 

 flour, J. M. Hamill {Rpts. Local Govt. Bd. [Ot. Brit.], Puh. HeaUli and Med. 

 Buhjs., n. ser., 1911, No. J,9, pp. 1-33; rev. in Brit. Med. Jour., 1911, No. 2624, 

 pp. 881, 8S2). — In this digest of data, which includes the author's own laboratory 

 work and personal observations in mills and bakeries, as well as the repoi-ts 

 of other investigators, the source of supply of wheat and flour, milling and grad- 

 ing, factors which determine quality, bleaching processes, their effects, the 

 addition of so-called "improvers" in flour, and similar matters are considered. 



The general conclusions reached are unfavorable to bleaching and to the use 

 of so-called " improvers." 



" The alterations in and the additions to flour which result from a high 

 degree of bleaching by nitrogen peroxid can not be regarded as free from risk 

 to the consumer, especially when regard is had to the inhibitory efi'ect of the 

 bleaching agent on digestive processes and enzyms. Even in the case of flour 

 which is bleached to the small extent which is at present ordinarily practiced, it 

 would in present knowledge be unwise to conclude that the process is attended 

 by absolute freedom from risk. The fact that bleached flour has been shown 

 to be something more than natural flour, the color of which has been modified, 

 Is also of importance in considering whether bleached flour may properly be 

 represented as genuine flour. ... , 



" With regard to other substances w^hich have been represented as ' improvers,' 

 it may be said that the indiscriminate addition of powerful chemical substances, 

 such as hydrofluoric acid, phosphorus pentachlorid, and the oxids and sulphids 

 of phosphorus, to flour is most dangerous." 



The author states that the use of cereals other than wheat in the milling 

 of flour is not common in England, though he cites an instance of the addition 

 of maize to flour and to self-raising flour. 



" The increasing activity which is now being displayed in the use of different 

 articles as additions to flour must be regarded with considerable apprehension. 

 It does not appear desirable that such an indispensable foodstuff as flour, the 



