THE MODERN POTATO PROBLEM 243 



above this temperature. The maximum sugar content 

 found in potatoes after storage at a given low tempera- 

 ture varies with time of year and with individual tubers, 

 young tubers accumulating less sugar than older ones. 

 Muller-Thurgau found that the sugar in potatoes after 

 a period of storage at low temperature is changed again 

 into starch when the tubers are exposed for from eight to 

 ten days at ordinary room temperature. This dis- 

 covery has been confirmed by other workers on a large 

 number of different varieties and is a practical means of 

 removing from potatoes their undesirable sweetness. 

 More recent work has shown that the room temperature 

 must not be too high because potatoes which have be- 

 come sweet will not lose their sugar at temperatures as 

 high as 80 to 85 F., but may continue for a time to ac- 

 cumulate more sugar. 



Respiration is a vital process common to all living 

 things. Breathing is just as essential to the life of a 

 potato as it is to the life of man, although this fact is 

 not generally appreciated. The intensity of respiration 

 in potatoes varies with the storage temperature, the 

 higher the temperature up to a maximum of about 

 1 10 F. the greater the respiratory rate. In the process 

 of respiration, oxygen and carbohydrates, as sugar and 

 starch, are consumed and carbon dioxide, water and 

 heat are produced. The accumulation of these pro- 

 ducts in storage is injurious to potatoes, therefore ven- 

 tilation is just as essential to the health of a potato as it 

 is to the health of animals. In extreme cases of high 

 temperature and poor ventilation, death of the inter- 

 nal tissues of potatoes by suffocation may occur, giving 



