884 



SCIENCE 



[N. S. Vol. XXXVI. No. 939 



gas by using a metal tank which would 

 maintain the required pressure. Into this 

 was forced the gas to an indicated pressure 

 of 15 pounds, which means that two vol- 

 umes of the gas were compressed into the 

 enclosed space of the apparatus. Under 

 these conditions the fruit became quite 

 edible in less than 46 hours. That is, the 

 time required to render the fruit non-as- 

 tringent under normal atmospheric pres- 

 sure was reduced to one fourth that time, 

 or rather less, as it later appeared, by in- 

 creasing the pressure twice. This was in 

 the autumn of 1911, at the time when no 

 further experiments were possible. Dur- 

 ing the early part of September, 1912, the 

 experimentation with supranormal pres- 

 sures was renewed. A special apparatus 

 had already been devised, composed of a 

 piece of four-inch gas pipe, suitably 

 capped, and supplied with a pressure 

 gauge and with outlets guarded by gas 

 cocks. This device enabled me to try the 

 effects of pressure reaching up to 90 

 pounds, or seven times the original dosage. 

 It is interesting to note that this high pres- 

 sure kills the frait in a few hours, so that 

 it becomes watery and unattractive. It is 

 nevertheless non-astringent. The effect, 

 however, of 45 and of 15 pounds pressure 

 separately were determined with consider- 

 able accuracy, with the following result. 

 The fruit exposed to 15 pounds pressure 

 became non-astringent in about 36 hours; 

 that subjected to 45 pounds in about 15 

 hours. We may say, therefore, that, as the 

 pressure of the carbon dioxid increases, the 

 period of time required for causing the ap- 

 parent disappearance of the tannin is de- 

 creased, and that the pressure goes up much 

 less rapidly than the period is decreased. 

 To make assurance doubly sure, the fruits 

 which were used in the experiment which I 

 have just briefly summarized ranged in 

 degree of maturity from being entirely 



green, of the green of grass, to orange-yel- 

 low, the next to final color stage of ripen- 

 ing, and it eventuated that fruits which are 

 entirely green can be rendered non-astrin- 

 gent in scarcely less time than those much 

 nearer maturity, thus leaving no doubt of 

 the significance of the experiments. To 

 state these results in everyday terms of 

 practical economics, we can say that it is 

 now possible to ship, say on September 

 first, green or near-green persimmons of 

 the variety mentioned from Alabama to 

 Montreal, where they should arrive in 

 good condition, hard and without bruise or 

 other blemish, on September third. Being, 

 however, quite inedible, and with a pros- 

 pect of remaining so for a month, or even 

 longer, if kept in cold storage, the fruit is 

 placed in a very simple and cheap appa- 

 ratus, and subjected to 45 pounds pressure 

 of carbon dioxid. The gas of course costs 

 very little, and can be easily obtained — it 

 is used in every soda water fountain. The 

 next morning, that of September fourth, 

 the fruits may be marketed, and if the 

 fruit dealers know human nature as well 

 as they appear to, the fruit would be read- 

 ily disposed of at a high price, if properly 

 displayed and advertised. Recurring to 

 the fruit of the date palm, the methods 

 which have been elaborated in Arizona, 

 when finally given finesse, will make it pos- 

 sible to utilize vast desert areas for the cul- 

 ture of the date palm, and so making an 

 otherwise useless waste contribute to hu- 

 man welfare. Of the cultivated persimmon 

 something the same may be said. In Cali- 

 fornia the culture of this tree has fallen 

 into desuetude, and in the southeast hun- 

 dreds of acres of persimmons are practi- 

 cally of no profit, for the reason that a 

 method of marketing edible fruit has been 

 wanting until now. It remains only to 

 perfect in detail for the several varieties of 



