PURE AND IMPURE FOODS. 



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differences being in favor of the latter. 

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The experiments are summarized as fol- 

 lows: 



"It has been said by some that the brown 

 eggs are richer than the white ones. This 

 statement is not borne out by a chemical 

 analysis, and the physical examination 

 proves that the main points of superiority, 

 though extremely slight, are possessed by 

 the white eggs. The minute differences 

 that are found between the 2 groups are 

 exceeded by variation between the varie- 

 ties within the same group. 



"We can, therefore, state as a conclu- 

 sion, both from a chemical and a physical 

 point of view, that there are practically no 

 differences, so far as the food value is con- 

 cerned, between the white-shelled and 

 brown-shelled eggs." 



The value of any food is determined, not 



alone by its composition, but also by its 

 digestibility. It is evident that if 2 foods 

 have the same composition, but, ow- 

 ing to physical properties or other cause, 

 the first gives up twice as much material 

 to the body in its passage through the 

 body as the second, it is much more val- 

 uable. In connection with other work r 

 the digestibility of eggs was studied at the 

 Minnesota Experiment Station. Experi- 

 ments were made by means of a pepsin 

 solution to determine the digestibility of 

 eggs cooked under different conditions. 

 Eggs were cooked 3 minutes at 212 F., 

 giving a "soft-boiled" egg, and 5 minutes 

 and 20 minutes at the same temperature. 

 An egg boiled 3 minutes and digested 5 

 hours in pepsin solution, compared with 

 one boiled 20 minutes and treated in the 

 same way, showed 8.3 per cent, undigested 

 protein in the former, against 4.1 per cent, 

 undigested protein in the latter. Under 

 similar treatment the egg boiled 5 minutes 

 gave 3.9 per cent, undigested protein. 



Another trial was then made, in which 

 the eggs were cooked 5 and 10 minutes in 

 water at 180 F. In both of these cases 

 the protein was entirely digested in 5 

 hours. 



These results would indicate that while 

 the method of cooking has some effect 

 on the rate of digestibility, it does not ma- 

 terially affect the total digestibility. The 

 results agree quite closely with those re- 

 ported some years ago by Rubner, a Ger- 

 man investigator, who found that 97.1 of 

 the protein of hard-boiled eggs was di- 

 gested. 



At the Minnesota Experiment Station a 

 digestion experiment was also made with 

 a healthy man in which a very considerable 

 portion of tLe nitrogenous material and 

 fat of the ration was furnished by eggs, 

 the other foods eaten being potatoes, milk 

 and cream. About 90 per cent, of the total 

 nitrogenous material and 90 per cent, of 

 the fat consumed were digested. In ex- 

 periments at the University of Tennessee 

 with healthy men on a diet of bread, milk 

 and eggs, from 90 to 95 per cent, each of 

 the protein and fat was digested. The 

 conclusion, therefore, seems warranted 

 that, as shown by composition and digesti- 

 bility, eggs possess the high nutritive prop- 

 erties which are popularly assigned to 

 them. 



For a number of years the United States 

 Department of Agriculture has been carry- 

 ing on food investigations in different parts 

 of the country. One of the objects was to 

 learn the kinds and quantities of food con- 

 sumed by persons engaged in various oc- 

 cupations and the relative cost of such 

 foods. Compared with other foods at the 

 usual prices, eggs at 12 cents a dozen were 

 considered a cheap source of nutrience; at 



