Date Endosperm for Self Digestion. 71 
was negative. It does not contain coagulable proteid, for on boiling with 
acetic acid in several dilutions no flocculation occurred. Care was taken to 
acidify after boiling and not before. On standing twenty-four hours after 
boiling there was so sediment. Prompt disappearance of turbidity on 
acidification suggested the presence of phosphates (tribasic calcium phos- 
phate). On testing with molybdic solution a fine yellow precipitate fell 
promptly, and on standing twenty-four hours an abundant yellow sediment 
settled (ammonic-phospho-molybdate). The extract, in contact with con- 
centrated nitric acid, failed to give even the slightest turbidity at junction 
or anywhere, which suggested the absence of all forms of proteid matter 
except perhaps secondary proteoses and peptones. The xanthroproteic 
reaction is doubtful, because the extract has a faintly yellow colour and 
a slight opalescence. The colour, slight as it is, turns to orange with alkali 
(NaOH and NH 4 OH), and similar change occurs with concentrated nitric 
acid, the colour in the latter case deepening on addition of alkali. Revers- 
ing the order of addition reverses the effects, or if heat is generated other 
colours, such as brown or reddish-brown, are produced. The colouring 
matter does not react sharply however. The same tests with commercial 
tannin did not give identical results, although various colourations were 
obtained. Dilute alkali causes the change of colour but dilute acid does 
not. The opalescence is, however, destroyed by both reagents. Glacial 
acetic acid does not produce visible change. Mineral acids, however, if 
concentrated, seem to have decided positive effect. 
Negative results were obtained in the following tests for proteids : 
Mayer’s reagent, Millon’s reagent, acetic acid and potassium ferrocyanide, 
and boiling in an acidified, saturated solution of ammonium sulphate. The 
latter solution, after filtering, was negative in the Biuret test. The latter 
reaction and the xanthroproteic test are not reliable with the extract because 
the colour produced by the alkali or strong acid obscures any evidence 
of change. 
The extract reduces Fehling’s solution if not too much reagent is used. 
If some freshly prepared reagent is diluted and boiled, and then the extract 
be added slowly, a prompt reduction occurs very soon. If the reagent 
is present in excess the reduction may not occur. In some cases I noted 
a heavy flocculation without reduction. This flocculation was found to 
be produced by the copper sulphate alone. On removing the precipitate 
the filtrate was promptly reducing. That this reduction was not due to 
tannin is certain because the test with ferric chloride was negative. 
The reaction with phenylhydrazin is positive. Carbohydrates insoluble 
in alcohol are present, and they may be fractionally precipitated with 
different strengths of alcohol, but very little precipitation occurs after 
a concentration of 80 per cent, is reached. The substance precipitated 
by alcohol when dried is of a dirty white colour and partially soluble 
