Am.  Jour.  Pharm. 
April,  1896. 
Laboratory  Notes. 
195 
adulterated  oil  the  time  is  much  extended,  varying  with  the  amount 
and  nature  of  the  adulterant. 
The  process  yields  only  approximate  results.  Duplicates  vary 
from  each  other  as  much  as  2  per  cent. 
The  following  table  contains  the  analytical  results  obtained  from 
six  samples  of  oil  of  cassia  : 
No. 
Sp.  Gr. 
at 
150  c. 
Per  Cent. 
of  Al- 
dehyde. 
Solubility  in 
70  Per  Cent. 
Alcohol. 
Solubility  in 
Alcohol. 
Reaction 
with  Lead 
Acetate. 
Rendered 
Turbid  at 
Per  Cent 
of 
Residue. 
1 
1*0566 
79"5 
Soluble. 
Soluble. 
None. 
6*23 
2 
1*0692 
64*0 
Soluble. 
Soluble. 
None. 
9-84 
3 
1-0452 
56*0 
Insoluble. 
Soluble. 
Precipitate. 
180  C 
12*71 
4 
1*0490 
64*0 
Insoluble. 
Soluble. 
Precipitate. 
12°  C 
13*61 
5 
1*0428 
54  'o 
Insoluble. 
Soluble. 
Precipitate. 
20°  C. 
12*87 
6 
1*0062 
40*0 
Insoluble. 
f  Insoluble  in ) 
\  equal  parts.  J 
Precipitate. 
7 
0*8168 
Insoluble. 
Insoluble. 
None. 
8°C 
No.  1  was  obtained  from  a  well-known  house,  and  guaranteed  to 
be  pure.  No.  2  proved  pure  according  to  the  U.  S.  P.  requirements, 
but  contained  a  low  percentage  of  aldehyde.  Nos.  3,  4  and  5 
were  taken  from  three  original  containers  selected  from  one  con- 
signment. The  containers  were  sealed  and  marked  Yan  Loong, 
which  usually  represents  a  high-grade  oil.  No.  6  was  a  known  mix- 
ture of  oils  of  cassia,  rosin  and  copaiba.  This  mixture  was  made 
to  test  the  accuracy  of  the  aldehyde  process  in  the  presence  of  these 
substances.  They  did  not  vitiate  the  results.  No.  7  was  petroleum 
oil,  obtained  from  one  of  the  containers,  having  been  added  in  excess 
of  saturation. 
The  residue  in  all  samples  except  No.  1  was  excessive  and  hard 
to  brittleness.  The  normal  residue  varies  from  5  to  8  per  cent.,  and 
is  soft,  never  hard.    Ten  per  cent,  is  allowable  in  extreme  cases. 
ELM  BARK. 
That  elm  bark  does  contain  starch  has  been  clearly  proven  by 
Professor  Lloyd.1  Exactly  what  it  is  that  interferes  with  the  ordi- 
nary starch  test  is  not  known.  It  is  even  impossible  to  detect  the 
starchy  matter  with  certainty,  with  the  aid  of  a  microscope  magni- 
1 1895,  Am.  Jour.  Pharm.,  67,  459. 
