January 7, 191 5] 



NATURE 



509 



It acquires these properties again directly small 

 quantities of electrolytes are present, and it is 

 argued, therefore, that the physical properties of 

 gluten are largely controlled by the presence of 

 salts. The analytical study of strong and 

 weak flours, made by Prof. Wood, in following 

 this clue, indicated that the former contained a 

 larger proportion of phosphates : this gave the 

 stimulus to Mr. A. E. Humphries — a practical 

 miller — to try the addition of an extract of phos- 

 phates from bran to a weak flour, and when this 

 addition proved advantageous in increasing the 

 strength, the eff"ect of adding small quantities of 

 pure phosphoric acid was tried in its turn. A 

 great deal of painstaking research has been 

 necessary for the elaboration of the new technique 

 of improving flour, and it is now commercially 

 possible to impart the qualities of strength to a 

 weak flour, so that it works better in the dough, 

 has an increased water absorption, and gives a 

 larger loaf of lighter texture, which is more 

 easily digested than when untreated; One result 

 of the treatment, which is of the highest national 

 importance, is that it enables a larger proportion 

 of English wheat to be used in the bread mixture. 

 Notwithstanding all that is said by food reformers 

 and agitators in the daily Press, the public do 

 demand a certain degree of lightness and texture 

 in their daily bread, for which the presence of 

 a considerable proportion of strong foreign wheat 

 in the mixture is essential. This is especially 

 the case in the large manufacturing towns in the 

 North : any sceptic as to the difference can easily 

 make the experiment of comparing the bread from 

 two kinds of flour at his own table. 



English wheats as a class yield weak flours, 

 characterised by their excellent flavour. Since 

 they can only be used by the baker to a limited 

 extent they fetch a correspondingly lower price 

 on the market, and to-day are very largely used 

 for household purposes where strength does not 

 matter. The possibility of using a considerably 

 increased percentage of home-grown wheat in the 

 bread mixture is bound to have a favourable 

 effect on the price, the more so as the small 

 country miller can make use of the local supplies 

 near at hand and will be much less dependent 

 on the supplies of foreign wheat, on which he has 

 to pay freight from the ports of entry where the 

 large milling concerns, with which he is in com- 

 petition, are usually situated. Chemical science 

 has thus rendered a service which promises to be 

 of the utmost importance to the farmer and the 

 country miller. 



It is, of course, necessary that a close control 

 should be exercised over the materials allowed 

 to be used as improvers, and nothing but the 

 spraying with soluble electrolytes in minute quan- 

 tities should be allowed, anything in the nature 

 of loading the flour being strictly prohibited. 

 There is still much prejudice to be overcome 

 against any scientific treatment of wheat, although 

 the baker is allowed free latitude to make the 

 best possible looking loaf from the flour available 

 — an obviously irrational position. 



NO. 2358, VOL. 94] 



Returning to the scientific aspect of the differ- 

 ence between strong and weak flours, it would 

 appear to be yet another instance of those elusive 

 problems in the chemistry of organic colloids such 

 as are concerned in most physiological problems 

 and most of all in that of life itself. The state 

 of aggregation of the colloid and its susceptibility 

 to this and that alteration, owing to the presence 

 of electrolytes of acidic or basic character, as 

 manifested by changes in the physical properties 

 is a general problem which is engaging the atten- 

 tion of many workers. In the case of flour, 

 sufficient has been done to enable great advances 

 to be made on the purely utilitarian side, though 

 their theoretical explanation may be still veiled in 

 obscurity. 



Although strength in flour has been traced as 

 due to the state of the colloid protein brought 

 about by the presence of a certain proportion of 

 electrolytes, our knowledge is still too indefinite 

 to enable the farmer to produce a strong wheat 

 by appropriate manurial treatment. The Cam- 

 bridge School of Plant Breeders has offered good 

 evidence that strength is a factor in the Mendelian 

 sense, and it is considered possible by appropriate 

 selection to obtain a wheat suitable for English 

 soils which will combine strength with the equally 

 important factors of yield and good straw. The 

 efforts of the Home-grown Wheat Committee to 

 encourage the growth of strong wheats in this 

 country have met with only partial success, 

 because, as a rule, strong wheats give poor yields 

 and inferior straw. Much further research is 

 necessary, which can only be done effectively at 

 agricultural stations, such as Rothamsted, or by 

 the agricultural departments of the universities. 

 The composition of the flour is due to the state 

 of maturation of the wheat berry at the time of 

 harvesting, and it will be valuable to know the 

 strength of the wheats produced on the individual 

 plots at Rothamsted with different manurial 

 treatment. 



However, as shown above, the short cut which 

 the miller is able to take renders him much more 

 independent of the nature of his wheat supply, 

 and it is probable in consequence that the con- 

 siderable difference in price between strong and 

 weak wheats will disappear to a large extent in 

 the near future, so that the incentive to the farmer 

 to grow strong wheats in this country will dis- 

 appear. That they can be grown has been 

 proved. E. F. Armstrong. 



THE FOOD OF BRITISH WILD BIRDS. 



SCIENTIFIC investigations concerning the 

 ' economic importance of our British wild birds 

 are of comparatively recent date, so that at 

 present the sum total of our knowledge is only 

 limited. To arrive at the precise economic value 

 of each of our commoner species is a task of no 

 mean magnitude, and yet it is slowly but surely 

 being forced upon the minds of all thinking people 

 who are concerned with the produce of the land 



