74 
Pond . — The Incapacity of the 
Demonstration of tannin in the en do carp. The thin membranous 
endocarp may be obtained in quantity as a chaff by sifting the powder, 
especially after the first time through the mill. On boiling some of this 
endocarp chaff in water, a light brown solution was obtained, which gave 
with ferric chloride a brown precipitate and a brownish green filtrate. By 
using a more dilute solution of the reagent a typical blue green colour 
without a precipitate was obtained, On adding lead acetate a grey pre- 
cipitate fell leaving a water clear filtrate. Potassium ferrocyanide caused 
a grey precipitate to fall. Iodine gave a reddish brown precipitate. 
A cold aqueous extract of the endocarp chaff gave a typical reduction 
of Fehling’s solution, probably due to the reducing sugar held by the 
membranes. Another portion of chaff, after being washed until an hours 
aqueous extract at ordinary temperature did not reduce Fehling’s solution, 
was extracted with boiling water. This extract reduced Fehling’s solu- 
tion, presumably because of the tannin rather than because of sugar. 
That tannin was present was made certain by the test with ferric chloride. 
Further, this extract gave the same colour reaction with alkali as the 
powdered endosperm from which the tannin was not obtained after long 
digestion in cold water. The endosperm substance entirely freed from 
endocarp substance by scraping the dry seed does not develop this colour 
with alkali. Thus it seems probable that the endosperm powder prepared 
as previously described above contains so little tannin or associated 
substances that not enough goes into solution in cold water to react with 
ferric chloride, but that enough is present to produce the change noted 
when alkali is added. 
Recapitulation of preceding data. The facts of special interest now 
revealed are : the endosperm contains reducing sugar, the endocarp con- 
tains tannin, the only proteid present in significant amount is the nucleo- 
proteid. 
Experiment No. 1 . Is the aqueous extract of the resting endosperm 
auto-hydrolytic? For this test 400 grms. of powdered endosperm were 
(KOH, 2 per cent.) and reprecipitated by slight acidification with dilute acetic acid. This process 
was conducted three times. The filtrates were amber coloured. The final precipitate seemed as 
deeply coloured as the first. The filtrates were free from phosphate. The precipitate contained 
phosphorus. On digestion in pepsin-hydrochloric-acid (2 per cent, each), a slight residue 
resembling the original precipitate remained, containing phosphorus. It was soluble in dilute 
alkali and appeared to be a nuclein or a mixture containing it. Hydrated with 2 per cent. HCL 
a deep red solution was formed, and a brownish black, flocculent material collected. The latter was 
slowly soluble in dilute alkali and, after being reprecipitated with acid, the colour remained the 
same and no effort was made to determine the nature of the latter. The filtrate was made strongly 
alkaline with NH 4 OH. Treatment with an excess of ammoniacal silver solution had no effect. 
There was no precipitate of silver-purin compounds after standing twenty-four hours. These observa- 
tions indicate that the original precipitate is not a pure substance. It contains not only nucleoproteid 
but apparently the colouring matter already noted. It is possible also that other substances or com- 
pounds of nucleoproteids are present, and further study with more material would be necessary to 
establish definite conclusions. 
