140 
Practieal  Notes. 
/Am.  Jour.  Pharm. 
1      Mar.,  1883. 
Leaves. — The  leaves  which  are  cleared  from  the  branches  that  are 
barked  are  carefully  preserved  and  dried,  and  afford  by  distillation 
Cassia  oil.  A  large  number  of  leaves  are  sent  to  Canton,  where  I  was 
told  the  operation  of  distilling  is  performed. 
"Iwigs. — These  are  removed  from  the  cut  branches  at  the  same  time 
as  when  the  leaves  are  obtained.  They  are  a  marketable  commodity 
for  native  uses. 
"Buds. — Cassia-buds  are  the  immature  fruits.  They  are  gathered 
when  about  one-eighth  grown.  Buds,  and  the  seeds  which  are  annually 
required  for  sowing,  are  obtained  from  the  trees  ten  years  and  upwards 
of  age  that  are  left  standing  at  about  fifty  and  a  hundred  feet  apart 
amongst  the  trees  which  are  cut  down  every  six  years  for  their  bark. 
These  seed-bearing  trees  are  not  cut  unless  there  is  a  demand  for  the 
very  thick  bark  on  their  trunks,  when  some  of  the  trees  which  can  be 
conveniently  spared  are  sacrificed. — Phar.  Jour,  and  Trans.,  January 
20,  1883. 
PRACTICAL  NOTES  FROM  VARIOUS  SOURCES. 
By  the  Editor. 
The  Permanganate  Test  for  Benzoic  Acid.  Gehe  &  Co.,  have  observed 
that  benzoic  acid  sublimed  from  benzoin,  when  dissolved  in  not  per- 
fectly pure  acetic  acid  and  reprecipitated  by  water,  would  respond  to 
Schacht's  test  for  benzoic  acid  from  Siam  benzoin.  They  liave  further 
observed  that  benzoic  acid  sublimed  from  Siam  benzoin  at  a  tempera- 
ture not  exceeding  125°C.  is  white,  and  when  tested  according  to  the 
new  German  Pharmacopoeia,  with  potassium  permanganate  will  after 
8  hours,  show  a  brown  color,  the  same  as  benzoic  acid  prepared  from 
Palambang  benzoin,  urine  or  toluol.  O.  Schlickum  has  made  similar 
observations.  The  first  portion  of  benzoic  acid  obtained  bv  sublima- 
tion, was  white  and  remained  white,  and  did  not  affect  the  test ;  the 
acid  subsequently  obtained  was  yellowish  and  reduced  the  permanga- 
nate, which  action,  however,  gradually  diminished  in  consequence  of 
the  resinification  of  the  empyreumatic  oil.  Benzoic  acid  containing 
cinnamic  acid  will,  of  course,  reduce  permanaganate,  but  will  also 
thereby  develop  the  odor  of  oil  of  bitter  almonds. — Phar.  Zeitung,  1882, 
p.  617,  780,  and  792. 
Recognition  of  Blue  Colors. — Indigo  is  decomposed  by  heat  and  decol- 
orized by  chlorine,  hypochlorites  and  nitric  acid.    Prussian  blue  is 
