1544 The Cornell Reading-Courses 



of calcium and phosphorus, a relatively high percentage of iron, and a 

 very high percentage of the base-yielding potassium. 



From the standpoint of acid-forming and base-forming qualities it 

 is fairly exact to say that one medium-sized potato furnishes enough bases 

 to neutralize the acids of two average slices of roast beef. Now if we 

 should substitute rice for potato in such a meal, we should find that, w'hile 

 rice supplied the necessary starch, it did not serve to counteract the acids 

 produced by the meat, but rather increased them. Consequently we 

 should have to restore the balance by adding a vegetable or a fruit or both. 



Another property, or constituent, possessed by the p6tato is of consider- 

 able importance although it is not yet fully understood. For want of a 

 better name it is often called vitamine, because it is essential to life. 

 Speaking of the property of preventing scurvy, possessed by fruits, vege- 

 tables, and milk. Dr. Sherman-^ says: "The e\adence has seemed to 

 favor the view that this property is chiefly due to the predominance 

 of base-forming ash constituents, but recent work indicates that vitamines 

 must also be taken into account in this connection." This makes it 

 appear that there is still more to be learned about the constituents of 

 the potato that make it a valuable article in our meals. In this regard 

 it is especially beneficial in a dietary in which white bread is used, because 

 in the refining process the wheat loses this vitamine property, or con- 

 stituent. 



Cost as compared with flour and bread 



The low price of the potato has been mentioned as one cause of its ex- 

 tensive use as food. A comparison of the values to be obtained from ten 

 cents' worth of potatoes, of patent flour, and of white bread, respectively, 

 shows the following: When potatoes are selling at 60 cents a bushel, or 

 I cent a pound, after removing the inedible portion (in this case the skin) 

 the cost of the edible portion is really 1.2 cents a pound; when they are 

 selling for $1 a bushel the cost of the edible portion is 1.9 cents a pound. 

 Patent flour at $1.10 for 25 pounds costs 4.4 cents a pound. White 

 bread, averaging twelve ounces to a five-cent loaf, costs 6.6 cents a pound. 

 In ten cents' worth of each of these three articles, potatoes give from 62 

 to 99 grams of protein (depending on the price paid), flour 115 grams, 

 and bread 64 grams. Comparing the energy value, one of the main pur- 

 poses for which these foods are usually included in our meals, potatoes 

 furnish from 2362 to 3780 Calories,* flour 3639 Calories, and bread 1773 

 Calories; thus, from potatoes at either price we are getting considerably 

 more energy than from bread. Of the minerals, ten cents spent for potatoes 

 may buy from three to four times as much calciimi and from three to 



'H. C. Sherman. Food products, p. 356. 1015. 

 ' * In measuring the energy value of food a unit is necessary, just as in measuring weight. The Calorie 

 is this energy, or heat, unit. 



