152 THE POTATO 



greatest directly after digging, and in February the 

 losses were higher than the month before or after. 

 The size of the tuber, or whether the variety was early 

 or late, had no perceptible influence. The three early 

 varieties lost from 4.87 to 8.48 per cent., the five medi- 

 um-early varieties from 4.55 to 6.78 per cent., and the 

 four late varieties 5.71 to 7.28 per cent. These losses 

 are believed to be lower than those usually assumed 

 and observed. The loss of weight of these tubers 

 from May to October was 21.57 P er cent., considerably 

 more than their loss from October to May i . As soon 

 as the sprouts begin to grow the loss is rapid. 



Nobbe found that about 75 per cent, of the loss of 

 potatoes in storage is due to loss of water and 25 per 

 cent, to respiration. As the potato is alive and 

 breathes, its existence depends upon its using some of 

 its stored-up energy. A ferment changes some of its 

 starch into sugar, and this sugar is used to furnish 

 energy. At low temperatures sugar formation contin- 

 ues, but respiration and the use of the sugar diminishes, 

 and at 30 F. to 28 F. (2 to 4 below freezing-point) 

 respiration almost ceases; hence, frozen potatoes taste 

 sweet because of the accumulation of sugar. 



E. Wollny believes that between 32 and 50 F. is 

 the best range of temperature for holding potatoes. 



The actual losses which may occur in storage as the 

 result of disease cannot be definitely stated. 



