CHAPTER XV 



CHEMICAL COMPOSITION AND FEEDING VALUE 



Composition. Early attempts were made to deter- 

 mine the food value of the potato by means of chemical 

 analyses. In 1795 Pearson reported "Experiments 

 and observations on the constituent parts of the potato 

 root." Einhof published analyses of the potato in 

 1805, as did Vanquelin in 1817. Rather more than 

 fifty years ago Emmons in this country reported anal- 

 yses. Lawes and Gilbert devoted considerable time to 

 the study of the composition of potatoes, and more re- 

 cently various agricultural experiment stations, nota- 

 bly the Connecticut State and the Minnesota Agricul- 

 tural Experiment Stations, the Division of Chemistry, 

 U. S. D. A., and various European institutions have 

 been investigating the problem. The approximate 

 chemical composition of a number of varieties is : 

 Water, 75 per cent.; protein, 2.50 per cent.; ether ex- 

 tract, .08 per cent.; starch, 19. 87 per cent.; fibre, .33 per 

 cent.; other non-nitrogenous materials, .77 per cent.; 

 ash, i per cent. A more extended analysis is taken 

 from the Vermont Experiment Station, report 1901: 

 TABLE XII 



1 66 



