The great potato drive to utilize the surplus of our huge 1917 potato-crop, 100,000,000 bushels above normal, has fixed in every one's mind the interchangeableness of these two foods.    From Wordnik.com.  [Food Guide for War Service at Home Prepared under the direction of the United States Food Administration in co-operation with the United States Department of Agriculture and the Bureau of Education, with a preface by Herbert Hoover] Reference

In explanation of this apparent interchangeableness, we must recollect that no character is simple, and that in twins who strongly resemble each other, every expression in the one may be matched by a corresponding expression in the other, but it does not follow that the same expression should be the prevalent one in both cases.    From Wordnik.com.  [Inquiries into Human Faculty and Its Development] Reference