8 EXPERIMENTS OX PROCESSING PERSIMMONS. 



certain giant cells of the pulp. The size of these cells is of itself 

 quite remarkable. They are large enough to be seen easily with the 

 naked eye, sometimes reaching a length of 1 mm, but vary greatly 

 in size and shape according to the species of persimmon. The tannin 

 seems to be collected in them in the shape of a liquid having a higher 

 refractive index than the contents of the ordinary cells surrounding 

 them. Quite similar cells with apparently a similar function, i. e., 

 the storage of tannin, occur in the carob-bean pod (Ceratonia siliqua), 

 and have been observed by Mr. Walter T. Swingle in the tissues of 

 the date fruit, which, like the persimmon, is very strongly astringent 

 when green and loses its astringency when ripe. 



In a partly ripe persimmon these giant cells do not break imme- 

 diately when they are placed in the mouth but absorb water from the 

 saliva, swell slowly, and burst, emptying their contents of thick 

 liquid tannin-bearing substance on the tongue. Probably it is for 

 this reason that hi biting into a half-ripe persimmon it takes a fraction 

 of a minute to get the full force of the astringency. 



In the ripening process the contents of these cells undergo a change, 

 becoming more refractive and so hard that water produces but little 

 swelling effect. The fruit then entirely loses its astringency, pre- 

 sumably as a result of the hardening of the contents of the giant cells. 

 Miss K. G. Barber, of the Bureau of Chemistry, finds that processing 

 causes a similar change in their contents. 



Encouraged by the first experiment, Mr. Roeding processed, a 

 second lot of persimmons in the autumn of 1906 and sent one of the 

 sake tubs full of treated fruit to the writer for examination. These 

 fruits were exhibited at a meeting of the Washington Botanical 

 Society and specimens were sent to some of the principal fruit dealers 

 in New York and the verdict was that the use of this method would 

 make of the kaki a very desirable commercial fruit within a very 

 few years. 



As it seemed desirable that this or some better method of treating 

 the persimmons be tried in a section where the fruit is grown, cooper- 

 ative arrangements were made by the Office of Pomological Investi- 

 gations with Mr. William Macklin, of Dinsmore, Fla., one of the 

 largest growers of persimmons in America, and the results obtained 

 were carefully studied during the autumn of 1907. Throughout 

 the four seasons that these experiments were made, the writer has 

 been an interested and sympathetic spectator, and has passed judg- 

 ment on the relative freedom from tannin of the different experi- 

 mental lots of fruit. 



The substitution of carbonic-acid gas for the fumes of sake, the 

 rice wine of the Japanese, and the use of dry starch to prevent the 

 cracking of the fruit during the processing, are two very important 

 matters which have resulted from the experiments, while the differ- 



