230 



SCIENCE 



[N. S. Vol. XXXVII. No. 945 



it ; is indeed rather a result of the death of the 

 tannin idioblasts," and can be seen to proceed 

 in vitro equally well, either spontaneously, but 

 rather slowly, or rapidly under the effect of 

 certain acids. It seems true, therefore, that 

 the cause of nonastringency in all the vari- 

 eties, whether they are the so-called nonas- 

 tringent kinds or not, is the same. I have ad- 

 vanced an explanation of the phenomenon else- 

 where" and the present issue does not call for a 

 restatement. 



In view of the possibilities in the case, there- 

 fore, I am bound to retain faith in the signifi- 

 cance of the experiments upon which I based 

 the conclusion that the higher the pressure of 

 carbon djpxide, the shorter the period re- 

 quired to render the fruit nonastringent, es- 

 pecially as repetition and extension, in 1912, 

 of the experiments of 1911 have discovered no 

 discordant evidence. 



The experiments were done during the first 

 two weeks of September, 1912, at Auburn, Ala. 

 The receivers used were four in number, all 

 alike in construction. Each consisted of a 

 piece of four-inch gas pipe two feet long, 

 capped at both ends. A pressure gauge was 

 inserted laterally, while each cap carried a 

 gas cock, thus allowing the entrance and exit 

 of the gas and air. This apparatus was cheap 

 and eiScient, but was not altogether easy to 

 manage. It was necessary to work in a ma- 

 chine shop where pipe vises and large wrenches 

 were at hand to screw home the large cap 

 which had to be removed in order to examine 

 the fruit. Graphite " dope " was used to make 

 the joints tight. Though a pressure of 90 

 lbs. was in one case maintained for 24 

 hours, it usually fell a little, due to insuffi- 

 cient skill in getting every joint tight. The 

 fall was, however, slight in any case, and, in 

 view of the relations found, can be regarded as 

 affecting the result but negligibly. 



The fruits used were Hyakume, as stated, 

 and Tane-nashi. For a supply of the latter 

 I am indebted to Mr. C. L. Coleman, Fair- 



' Lloyd, F. E., ' ' The Behavior of Tannin in Per- 

 simmons with some Notes on Ripening," Plant 

 World, 14: 1-14, January 1, 1911. 



" Lloyd, I. c, note 5. 



hope, Ala., who was kind enough to send a 

 large basket of choice material. For the name 

 of this variety, I rely upon general acceptance 

 in Alabama. The fruit answers also to the 

 current horticultural descriptions. The Taber 

 129, which had been used in the experiments 

 of 1911, were excluded for the reasons above 

 stated. 



The condition of the fruit as regards ma- 

 turity was various, ranging from complete 

 greenness to partly orange, the intermediate 

 shades of yellow, yellow-green and yellow- 

 orange being represented — this in Hyakume. 

 The Tane-nashi ranged from pale yellow to 

 orange. It was found that the rate of be- 

 coming nonastringent was as rapid in the 

 green as in the more mature fruits so long as 

 they were under the influence of the carhon 

 dioxide. If, however, they were insufficiently 

 processed, and then kept exposed to the air, 

 the subsequent changes were more rapid in 

 the more mature fruits. Maturity then did 

 not modify the immediate effect, and the 

 range of condition in regard of maturity rules 

 out error due to difference of ripeness. The 

 fact is one, . moreover, of prime theoretical 

 importance. 



In charging the receivers, a corresponding 

 number of sets of fruits was chosen in such 

 manner that each set contained the same 

 range of color. The charge consisted of 8 

 fruits in each instance. Each fruit was se- 

 lected carefully for its soundness, and no 

 bruised or otherwise injured fruit was used, 

 except in the ease of the Tane-nashi, which, 

 on account of transportation, was in some 

 instances more or less bruised. This was, 

 however, found to have no immediate effect 

 on the rate of processing, though the keeping 

 of the fruit thereafter was affected, as was 

 true also of the other kinds. 



In the several experiments' pressures rang- 

 ing from normal to 90 lbs., were employed, 

 together with controls in air. By charging 



'While the results obtained with Tane-nashi are 

 in general accord with those from Hyakume, they 

 are not by any means as clear-cut and unequivocal. 

 I shall therefore withhold them from the present 

 discussion, but will embody them in a later account. 



