THE MONTHLY BULLETIN. 429 



Disappearance of starch. 



lodiii tests applied to freshly cut halves during ripening indicated 

 disappearance as the pear became ripe. The disappearance was grad- 

 ual and not complete until the pears were practically ripe. The starch 

 disappeared more rapidly from the region around the core than it did 

 from the outer portion of the fruit. 



Effect of date of picking on starch test. 



Pears picked at end of the tests gave practically as strong a starch 

 reaction with iodin as did those picked at the beginning of the season. 

 Therefore this criterion can not be used in judging ripeness. 



SUMMARY. 



1. Relation of Balling and acid to suitability of pears for shipping purposes. 



The pears picked on or after July 1, with one exception, ripened very 

 satisfactorily, although the fruit near the end of the season developed 

 more satisfactorily as regards flavor and aroma than that at the begin- 

 ning of the season. The sample which did not develop satisfactorily 

 was 11.9 Balling and .26 per cent acid, a composition not differing 

 greatly from that of pears which ripened satisfactorily. 



The tests should be started earlier in the season to obtain results of 

 more value on the above point. The Balling and acid tests or a starch 

 test by iodin do not seem to be of much value in judging the proper 

 stage of maturity to pick pears for shipment. 



2. Increase in Balling of pears on tree during period of tests. 



The Balling degree increased between the first and last samples as fol- 

 lows: Sacramento pears, 2.9 per cent; Auburn, .5 per cent; Martinez, 

 1.4 per cent. The length of time represented is three to six weeks. The 

 rate of increase is slow, and it is very doubtful if this test will prove of 

 much value. 



3. Size. 



Probably a minimum size will be of more value than a chemical test 

 in deciding the time of picking. Pears used in the above tests averaged 

 from 2.25 to 2.81 inches in diameter and 5.69 ounces in weight. From 

 the data at hand it seems safe to say that pears of this or greater weight 

 will ripen satisfactorily. For estimation of the size of the pears, prob- 

 ably either the diameter or weight could be used as a criterion. The 

 diameter can, however, be more quickly obtained than the weight. 



SUGGESTIONS. 



1. Determine whether there is any relation between the size of pear 

 and suitability for shipping purposes. 



2. Determine w^hether there is any relation between the specific 

 gravity of pears, as determined by floating in salt solutions of different 

 specific gravities, and the suitability for shipping purposes. 



3. Determine w^hether there is any relation between "coarseness of 

 grain" of pulp or color of seeds and suitability for shipping purposes. 



2—27106 



