THE NATIONAL GEOGRAPHIC MAGAZINE 



363 



: 



normal little; rat and stunted rat 



_ Two little rats of the same age, one normal, the other stunted by its mother's milk, 

 which was of poor quality because of faulty diet. From the experimental cages of Dr. Mc- 

 Collum. 



The other product is known as potato 

 starch flour, and is made by first grind- 

 ing the potatoes, pumping the pulp on a 

 screen, which takes out the coarse fiber 

 and skin, and then dropping this pulp into 

 vats, where, by means of running water, 

 all of the remaining fiber and much of 

 the protein and mineral salts are washed 

 out, leaving only the pure starch. 



This is the starch which prior to the 

 war was used by the cloth manufacturers 

 for the sizing of their fabrics. Now, 

 when wheat flour is scarce, it has come 

 into use for the making of high-class 

 pastries. It has not, of course, the nutri- 

 tive value of the natural potato flour. 



That the stabilizing of the potato crop 

 is of the utmost importance has been 

 recognized in Germany for many years. 

 But in the United States the price the 

 farmer receives varies very greatly, ac- 

 cording as there is a surplus or a scarcity. 

 When the potato harvest is a large one, 

 he is apt to lose money on his crop, and, 

 being discouraged, next year he puts in 

 something else. If there is a shortage in 

 that year potatoes bring exorbitant prices, 

 and he sees big money in them, and the 

 following year he puts in a big acreage, 

 as do thousands of others, and perhaps 

 the year is a good one for potatoes and 

 the yields are 25 per cent higher, and 



