312 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



work were chosen where part of the fruit was frozen while the re- 

 mainder was untouched by the freeze. Different types of fruit were 

 marked and only those with an apparently uninjured stem were 

 selected for the experiment. In one class the fruit was green and 

 normally would have increased in size. In another class the fruit 

 was yellow and almost ripe and would not increase in size like the 

 green fruit. In measuring the fruit the circumference was measured 

 in inches. The same observations were carried on in regard to the 

 growth of frozen lemons, and the results are given in the following 

 table : 



TABLE 14. AVERAGE INCREASE IN CIRCUMFERENCE OF FROZEN AND UNFROZEN 

 VALENCIAS AND LEMONS FROM JANUARY 24 TO JUNE 2, 1913 



Good fruit, 



full of juice Fruit Fruit 



and good slightly badly 



flavor frozen frozen 



inches inches inches 



Valencia, yellow fruit which was very 



nearly ripe at the time of the freeze 58 49 



Valencia, fruit green; thrifty groves not 



badly frozen 71 .56 



Valencia, fruit green; grove badly frozen .48 .34 



Valencia, fruit almost ripe and badly 



frozen -- -33 .10 



Eureka lemons one-half of the fruit on 



the trees frozen 71 .54 .32 



From this table we see that the fruits have grown in circumference. 

 In a few instances, however, the stem was found to be injured and 

 the fruit gradually decreased in size. The juice had almost disap- 

 peared in the badly frozen fruit, leaving it hollow. In the good fruit 

 the increase in circumference is approximately twice that of the badly 

 frozen fruit. The rind of frozen fruits increases in thickness (fig. 19), 

 thus probably taking nourishment, or at least water, from the tree.* 



SUMMARY 



1. The specific gravity of frozen citrus fruits, in general, is lower 

 than that of unfrozen ones. This is, however, not an absolute rule. 



2. The two classes cannot be absolutely separated, but the division 

 is sufficiently complete to make it commercially practical. Different 



* Note. Observations on various groves in the state lead the authors of the 

 first article in this bulletin to conclude that no noticeable effect was produced by 

 leaving the frozen fruits on the tree. Compare page 289. That the fruit when not 

 too badly frozen increases in size the authors of this paper have proven. Such 

 fruit, however, evidently losses in weight. H. J. Webber. 



