vm, a. 6 Pratt et al.: Nipa Palm 379 



while other unworked areas are overgrown and choked. The 

 former naturally support fewer palms of superior quality com- 

 prising a larger proportion of fruiting plants. A conservative 

 estimate for cultivated nipales, or nipa swamps, may be placed 

 at from 2,000 to 2,500 palms per hectare, of which 750 may be 

 depended upon to produce fruiting stalks and consequently be 

 available for sap collections. Proper attention in keeping the 

 swamps free from overcrowding and intelligent care in selection 

 would doubtless greatly increase the percentage of flowering 

 plants, and might raise the average individual production of 

 sap and its sucrose content. 



THE CHARACTER OF THE SAP 



The nipa sap collected in the above manner and transported 

 to the distilleries is of no value for the manufacture of sugar. 

 Many factors to be discussed later have resulted in causing more 

 or less complete inversion of the sucrose followed by alcoholic 

 and acidic fermentation. Nipa sap is very susceptible to changes 

 of this character, any of which are fatal to its utilization as a 

 source of refined sugar. 



The sap as it flows from the cut surface of the flower stalk 

 is water white, practically neutral, and possesses a character- 

 istic odor. The composition varies considerably, depending 

 upon the age of the flower stalk — or time that has elapsed since 

 it was first cut — the season, the location, and the individuality 

 of the palm. The tendency of nipa sap to undergo inversion 

 within a few hours after collection, even when great care has been 

 employed to obtain aseptic samples, and the impracticability of 

 laboratory work in the swamp render it difficult to obtain as many 

 analyses of fresh sap as could be desired. No preservatives 

 have been found efficient in preventing change in the character of 

 the juice without introducing a relatively large amount of foreign 

 material. The only satisfactory method is to collect the sap 

 directly in clean bottles and sterilize by heat within an hour or 

 two after starting the collection. 



The average nipa sap as it flows from the palm has approx- 

 imately the following composition: 



Density 15V15° 1.0670 



Brix 17.0 



Apparent purity 90.0 



Invert sugar Trace. 



Sucrose 15.0 per cent. 



Nitrogen 0.049 per cent. 



Ash 0.60 per cent. 



Sodium chloride 0.45 per cent. 



