RESISTANCE TO WOUNDING OF CERTAIN FRUITS. 



the spring was released by means 

 of a rack and pinion adjustment 

 until a quick drop in the needle 

 showed that it had penetrated 

 the epidermis of the fruit. The 

 reading on the scale of the in- 

 strument was then taken and the 

 weight required to balance this 

 tension on the spring determined. 

 The weight of the glass rod and 

 needle, minus the weight required 

 to balance the tension on the 

 spring, gives the pressure of the 

 needle on the fruit at the time it 

 punctures the epidermis. 



CONDITIONS OF THE TESTS. 



Five tests were made on differ- 

 ent regions of each fruit, and a 

 number of fruits, varying from 5 to 

 16, were used in all experiments. 

 The fruit was picked in the morn- 

 ing of the day the determinations 

 were made and tested at room tem- 

 perature and after being cooled in 

 the ice box. Tests were also made 

 on berries washed in tap water, in- 

 asmuch as berries are frequently 

 washed before packing and ship- 

 ping commercially. As already 

 mentioned, Stevens and Wilcox 

 have shown that the washing of 

 strawberries is beneficial. In a 

 number of cases the fruit was 

 tested the day it was picked, part of 

 it placed in the ice box and tested 

 later, and the remainder allowed to 

 stand in the ice box for 24 hours. 

 It was tested again on being re- 

 moved from the ice box and later 

 after it had had time to warm to 

 room temperature. The results 

 of these determinations with the 

 different varieties of the fruits are 

 given in Table I. The number of 



Fig. 1.— Apparatus used in determining the pres- 

 sure necessary to puncture fruits. 



