48 The Philippine Journal of Science 1922 
vigorous in a nipa swamp and often attack the tuba even before 
it drops from the stalk. If a strip of red litmus paper is laid 
against the cut end of a stalk, from which tuba is coming fairly 
rapidly, itis turned blue. If, however, a portion of the cut end 
is giving sap only slowly, that portion will turn blue litmus red. 
In case the flow is very slow the resulting tuba is strongly acid, 
and a characteristic white gelatinous deposit forms, in which 
yeast and bacteria develop rapidly. 
Similar rapid fermentation and gelatinous precipitate may 
always be observed in the ordinary tuquil’ used for collecting 
tuba. This may be reduced to a certain extent by using clean 
tuquils, especially in the first days of flow, during which the tuba 
evidently does not contain as much enzyme as later. This fact 
enables the tuba gatherers in certain swamps to make sirup or 
noncrystalline sugar from the first few days’ flow, collected in 
clean tuquils. It has been found possible at the Catarman Agri- 
cultural School to extend the sirup making throughout the time 
of flow if the tuquils are washed, disinfected with lime, and 
placed on the palms in the late afternoon. The night tuba, 
collected in the early morning, is boiled down to sirup, and the 
day tuba is used for vinegar. 
This sirup-making process is practically the same as that used 
in India to produce 300,000 tons of crystallized palm sugar an- 
nually.2 The composition of the palm sap (from the wild date 
and the toddy palm) is about the same as that from nipa, but 
it may be that the enzymes are not so active. The lower temper- 
ature of the Indian groves during the collecting season is doubt- 
less an important factor. At any rate, the Indian palm sap 
gives crystallized, though impure, sugar, while Philippine nipa 
tuba, treated in the same.way, gives only a sirup or caramel. 
Fermentation of tuba may be practically obviated by the 
precautions mentioned, but inversion, that is, conversion of the 
crystallizable sucrose into an uncrystallizable mixture of fructose 
and glucose, is not so easily prevented. Unless a preservative 
is used the boiled-down tuba is at best an edible sirup or non- 
crystallized caramel. 
PRESERVATION WITH TOLUENE 
The experiments with toluene described below were not under- 
taken with any idea of the commercial use of toluene, but rather 
*The Pampangan name for the bamboo receptacle which is hung on the 
palm stalk. Visayan names are lacob and salud; Spanish, bonbon. 
* Annett, H. E., and others, Memoirs Dept. Agr. in India, Chem. Series 
2 (1918) 281-389; 5 (1918) 68-116. 
