8 BULLETIN" 916, U. S. DEPARTMENT OF AGRICULTURE. 



when jarred. It is considered highly important to call the attention 

 of growers and shippers to this point, since under some circumstances 

 it would be entirely possible that a lot of potatoes or even other prod- 

 ucts might be undercooked considerably below the freezing point and 

 escape injury if they remained undisturbed till their temperature was 

 above the freezing point. If it should be found necessary to move 

 such a lot in order to protect them from further lowering of the 

 temperature, this should be very carefully done, having in mind the 

 danger of freezing as the result of jarring or jolting. These state- 

 ments seem justified and are supported by the results brought out by 

 the following experiments, which were conducted to determine the 

 amount and character of the disturbance necessary to cause freezing 

 when different varieties of potatoes are held at temperatures between 

 28° and 25° F. The same seven standard varieties before named were 

 used in these experiments. 



EXPERIMENT NO. 1. 



Duplicate lots of potatoes, consisting of a single specimen of each 

 variety, were held between 26° and 27° F. for 5^ hours. Then each 

 specimen in one lot was dropped from a distance of 4 feet to the 

 concrete floor. After 17 hours from the time they were dropped, 

 both lots were removed and held at ordinary room temperature 

 several hours before they were cut open. In the check lot only the 

 Irish Cobbler and the American Giant were injured. All specimens 

 in the treated lot were not only badly bruised, as might be expected 

 from the rough treatment, but they were all frost injured, as was 

 shown by extensive blackened vascular areas of the blotch type. 

 (PI. I.) None of the potatoes were frozen hard enough to cause 

 collapse of the tissues. 



EXPERIMENT NO. 2. 



Duplicate lots of one potato of each variety were held at 28° F. for 

 22 hours. One lot was then dropped as before and left for three 

 hours. Both lots were then removed. As before, at the lower tem- 

 perature all the dropped potatoes were bruised and showed extreme 

 freezing injury. In the undisturbed check lot only the Irish Cobbler 

 was injured. 



EXPERIMENT NO. 3. 



Duplicate lots of one potato of each variety were placed at 28° F. 

 for 24 hours. Each specimen from one lot was dropped from a dis- 

 tance of 2 feet, and after another 24 hours all were removed. On 

 the usual examination it was found that these potatoes were badly 

 bruised and showed extensive injury, as before, except the American 

 Giant and Spaulding No. 4 varieties, which showed no frost injury 

 and were not bruised. 



