viii, a, 6 Pratt et ah: Nipa Palm 383 



sap and that atmospheric influence causes the separation of 

 white, flocculent invertase which rapidly attacks the sucrose 

 present. He recommends lining the interior of clean tuquils 

 with thick lime cream, and states that sap collected in recep- 

 tacles so treated will remain unchanged for a longer period than 

 ten days. We have found that sap collected early in the season 

 of flow may be preserved in a satisfactory manner by this means, 

 provided the interval between placing the tuquil in position on 

 the palm and removing the accumulated juice be not over twelve 

 hours. There is no doubt but that invertase action is effectively 

 stopped in alkaline solution. The principal objection to this 

 method of collection lies in the fact that large amounts of lime are 

 absolutely essential and that an even distribution of alkalinity 

 is uncertain. The latter difficulty is inherent in this method 

 of collection and preservation. The tendency of juice dropping 

 slowly into tuquils containing lime is to stratify. The first 

 juice dissolves relatively large amounts of lime, and consequently 

 attains a density considerably higher than the fresh inflowing 

 sap. These heavy layers remain at the bottom, and are gradually 

 covered with juice containing less and less lime until a point of 

 neutrality is reached. This tendency is counteracted to a greater 

 or less extent by the lime clinging to the sides of the tuquil, but, 

 if this has been carelessly applied or if the cream used was of 

 insufficient consistency, the desired result is seldom accomplished. 

 The upper portion of neutral juice is rapidly acted upon by the 

 invertase present, 'and subsequently undergoes fermentation, the 

 harmful results of which need not be mentioned in detail. Not 

 only is sucrose destroyed, but invert sugar is formed, and the sol- 

 uble lime salts resulting from acid fermentation render the juice 

 difficult to handle in boiling and greatly reduce the percentage of 

 available granulated sugar. 



A large number of trials served to show that many of the 

 lime-coated tuquils contained acid-top layers of juice after twelve- 

 hour collections, and that this was the case in practically all 

 tuquils after twenty-four hours on the palm. The latter were 

 always covered with froth, and had developed a disagreeable 

 odor characteristic of fermented tuba. A simple and successful 

 method for obviating this difficulty will be discussed later. 



OTHER NIPA- ENZYMES 



We observed that many samples of nipa juice, although uni- 

 formly alkaline with lime, showed a gradual loss of sucrose, while 

 other samples could be so preserved for long periods of time 

 without change. Samples of juice originally containing 15 per 



