m.  Jour.  Pharm. 
July,  1898. 
A  Species  of  Commelina. 
323 
Basic  lead  acetate  caused  a  gelatinous  precipitate. 
Neutral  lead  acetate  yielded  a  precipitate  of  the  same  character. 
Barium  chloride  gave  no  precipitate. 
Silver  nitrate,  acidified  with  nitric  acid,  threw  down  a  brownish- 
white  precipitate,  which  was  soluble  in  ammonium  hydrate ;  on 
heating  this  ammoniacal  solution  a  reduction  to  metallic  silver 
occurred. 
Gold  chloride,  acidified  with  hydrochloric  acid,  was  reduced  to 
metallic  gold  on  heating. 
These  behaviors  showed  the  absence  of  tannic  and  gallic  acids, 
but  the  presence  of  some  other  substance  having  reducing  power 
on  salts  of  gold  and  silver. 
The  plant  material  that  was  left  undissolved  by  cold  water  was 
boiled  with  water  for  a  few  minutes,  the  mixture  filtered  and  the 
clear  filtrate  allowed  to  become  cold.  It  was  then  tested  with  potas- 
sium tri-iodide,  which  gave  the  characteristic  blue-color  reaction  for 
starch. 
Fig.  1. 
