176 



GIBBS. 



An invertase proferment or zymogen, also present in the sap, has previ- 

 ously been described in the chapter on the nipa palm. The large amount 

 of reducing sugars found in some of the samples is due to the length of 

 time which elapsed during their transportation from the provinces to the 

 laboratory in Manila and the lack of complete precautions to inhibit the 

 action of the invertase. Since no measurements of the flow of sap of these 

 four trees were made for an entire twenty-four hour period, the figures 

 for the daily flow are only approximate. It has been observed that this 

 rate is greatest just after tire surface has been newly cut. An increase of 

 as much as 50 per cent in the rate can be produced temporarily by fresh 

 cutting and since the majority of the samples was collected immediately 

 after cutting, it is probable that the estimated rates of flow are too great. 

 Nevertheless, it is evident that three of the trees had an astonishingly 

 large flow of sap, probably in the neighborhood of 30 liters for twenty- 

 four hours. The amount of sugar in the total sap flow can be estimated 

 about as follows : 



8ugar in total sap flow of the huri palm. 



Tree 

 No. 



Estimat- 

 ed daily 

 flow. 



Approx- 

 imate 

 sugar 



content. 



Daily 

 sugar 

 yield. 



Duration 

 of sap 

 flow. 



Total 

 sugar 

 yield. 



1 



2 



4 



Liters. 

 20 

 30 

 40 



Per cent. 

 14 

 8 

 9 



Kilos. 

 2.8 

 2.4 

 3.6 



Days. 



100 



135 



50 



Kilos. 

 280 

 324 

 180 



There is no reason for believing that these estimates of the yields of 

 sugar from mature trees are exaggerated. 



The sap richest in sugar obtained from the four buri trees as it flowed 

 from the tree had approximately the following composition: 

 15° 



Density 



^ 15° 

 Total solids 



Ash 



Acidity (as acetic) 



Sucrose 



Reducing sugars 



Undetermined solids 



1.0700 



17.0 per cent. 

 0.43 per cent. 

 0.06 per cent. 

 16.0 per cent. 

 Small amounts or traces. 

 0.51 per cent. 



FEBMENTATION OF THE SAP. 



With W. B. GONDEK and P. Agcaoili. 



As it flows from the tree and for a short time thereafter, the sap is 

 colorless, odorless and neutral or slightly alkaline to litmus paper and 

 phenolphthalein. If heated to boiling it becomes alkaline to both these 

 indicators and remains colorless about two hours longer than sap not 

 heated. 



A viscous, followed by a putrid fermentation, develops in the sap on 

 standing, when no precautions are taken to inhibit their action. Both 



