684 THE POPULAR SCIENCE MONTHLY. 



1,600 grains, or 3*66 ounces of fatty matter which are present in the 

 contents of 20 eggs may take the place of its '944 ounce of fatty 

 matter which are met with in the 2 pounds of bread and in the f 

 pound of lean meat, and of the 16 "320 ounces of starch and the other 

 carbo-hydrates which are present in the 2 pounds of bread. For it 

 may be fairly assumed that the properties of the nitrogenous and non- 

 nitrogenous compounds are as properly balanced in the egg and milk, 

 which are the two great typical forms of natural food, as they are in 

 the artificial combination of bread and meat of which Ave are speaking. 

 You may draw your own conclusions from the tables on the walls in 

 which these facts are set forth. 



0. I also find in these tables a curious correspondence as to the 

 amount of mineral matter in the three cases under consideration. The 

 proportion of mineral matter in the other constituents is as 1 to 18 in 

 the egg, as 1 to 17 in milk, and as 1 to 17 in the case of meat and 

 bread. 



31. This correspondence may not be quite so close as it seems to 

 be. In the case of the egg an uncertain amount of lime, probably a 

 large amount, ought to be added, for the shell becomes thinner and 

 thinner as the process of incubation goes on, in consequence of the 

 solvent action of the phosphoric acid which is generated by the oxidi- 

 zation of the phosphorus in the contents of the egg. In the case of 

 white bread (white bread was used in this experiment) the greater 

 part of the mineral matter, which is lodged chiefly in the husks of the 

 grain, is sifted out in the preparation of the flour from which white 

 bread is made. The earthy matter of the shell is certainly necessary 

 to the proper development of the bones of the chick, and in all prob- 

 ability the bones are not the only tissues which are in this case. A 

 dog lives long and thrives when it is fed upon brown bread, but not 

 when it is fed upon white bread. Scurvy also is a speedy consequence 

 of living upon salt meat, which differs from fresh meat chiefly in the 

 fact that the salts belonging to it have been transferred to the brine. 

 If the body is to be properly nourished, the mineral matters which are 

 contained in the different articles of food can not be excluded, that is 

 evident. And if these different articles of food are to be properly 

 digested, the common salt, in the food or taken along with the food, 

 may have a very important work to do in addition, for without it it is 

 not easy to see how the gastric juice could acquire that part of its 

 acidity which depends upon the presence of hydrochloric acid. 



C. I have always avoided fat and butter, on the supposition that 

 they would make me bilious and stout. I also thought that they were 

 specially indigestible. I knew that they were of great value as heat- 

 producers, as " elements of respiration," as fuel, and that the inhabit- 

 ants of cold countries could not get on well without an abundant sup- 

 ply of them, but it never entered into my head to suppose that they 

 might take the place of meat and bread. 



