248 



Food and its Digestion. 



These separate principles in their nncombinecl form are 

 not generally palatable, nor in the best state to be acted 

 upon by the digestive juices. Nature has mingled them 

 so as to adapt them to the taste, and also render them 

 better fitted for the purposes of life; and man seemingly 

 instinctively, mingles them, so as to form compound sub- 

 stances capable of fulfilling all the requirements necessary 

 in food. For example, bread and butter which is so 

 generally eaten throughout the world, will well illustrate 

 this fact. In bread we find the albuminoid principle in 

 the gluten of the wheat, the saccharine, in the starch ; and 

 also in the flour are found the mineral principles, to all 

 of which man instinctively adds butter, which is the olea- 

 ginous principle. 



Magendie, the French physiologist, to prove the neces- 

 sity of the combination of all these elements in food, 

 performed some interesting and instructive experiments. 

 For example, he fed dogs upon sugar, oil, and butter alone 

 — carbon and hydrogen elements — and found that for 

 one or two weeks they did very well ; but after that period 

 became weak and emaciated, and died after the diet had 

 been thus continued for a period of from 32 to 36 days. 

 Fed upon white bread and water, they lived for 50 days ; 

 if cheese and white of egg were added to the diet, they 

 lived a few days longer. No diet will prove nutri- 

 tious, no matter how rich it may be in any one of these 

 nutritive elements, unless there be the correct combination 

 of all, as we see exemplified by nature in milk, and as 

 man combines when he eats bread with butter, where we 

 have the nitrogenous principle in the gluten of the wheat, 

 the carbo-hydrate in the starch of the wheat with its min- 

 eral principles, and added to them the hydro-carbon of the 

 butter. 



The atmosphere which an individual breathes exercises 

 a very important influence on the nature and quantity of 

 the diet. When the air is cold and condensed, there will 

 be necessarily a larger amount of oxygen inspired, which 



