Am  Jour.  Pharm.\ 
Jan.,  1891.  / 
Method  of  Soap  Analysis. 
21 
bark  (100  parts)  with  a  mixture  of  10  parts  glycerin,  10  parts 
hydrochloric  acid  and  200  parts  water,  then  percolating,  finishing 
with  water  until  the  percolate  ceases  to  precipitate  with  sodium 
hydrate.  The  percolate  is  next  distilled  in  a  vacuum  of  700  mm., 
at  a  temperature  not  exceeding  400  C.  (this  is  regulated  by  placing 
the  retort  in  a  water-bath  kept  at  45 0  C.)  until  a  syrupy  liquid 
remains  in  the  retort ;  this  is  removed  to  a  tared  vessel,  the  retort 
being  rinsed  with  successive  small  portions  of  water  until  the  total 
liquid  weighs  90  grams ;  then  10  gm.  alcohol  are  added,  and  the 
extract  filtered.  By  the  above  process,  change  in  the  bark  con- 
stituents is  avoided  and  an  extract  obtained  only  slightly  darker  in 
color  than  the  bark  used.  A  temperature  of  65°-70°  C,  even  in  a 
vacuum,  is  sufficient  to  bring  about  decomposition  of  the  cincho- 
tannic  acid. 
The  distillation  of  cassia  oil  to  detect  addition  of  resin,  if  not  pro- 
perly carried  out,  may  lead  to  the  condemning  of  a  pure  oil ;  if  in 
the  distillation  the  retort  be  exposed  so  that  the  atmosphere  cools 
the  upper  portion,  the  distillation  proceeds  slowly,  and  as  much  as 
sixty  per  cent,  residue  is  obtainable  ;  but  if  the  retort  be  surrounded 
by  some  non-conducting  material,  like  asbestos,  the  distillation  is 
rapid  and  only  five  per  cent,  residue  is  obtained  from  the  same  oil. 
The  residue  in  the  first  case  has  all  the  characteristics  of  asphalt : 
solubility,  odor,  color;  while  in  the  distillate  are  found  water,  acetic 
acid,  phenol  and  hydrocarbons.  These  results  would  indicate  that 
the  asphalt  found  in  nature  was  produced  by  the  action  of  heat  and, 
probably,  pressure  upon  essential  oils  or  resins. — E.  Hirschsohn, 
Pilar m.  Ztchr.f.  Russl.,  1890,  692. 
A  METHOD  OF  SOAP  ANALYSIS. 
By  Dr.  T.  Pinette. 
The  following  method  embodies  a  simplification  of  the  usual 
process  of  soap  analysis.  It  requires  a  separating  funnel,  such  as  is 
used  by  B.  Rose  in  his  method  for  the  estimation  of  the  fat  in  milk. 
This  is  provided  with  a  stopper  and  tap,  holds  about  230  cc,  and  is 
graduated  up  to  200  in  half  cc.  Such  a  funnel  is  useful  for  many 
purposes,  and  should  certainly  be  employed.  The  analysis  is  carried 
out  by  dissolving  2  gm.  of  soap  in  boiling  alcohol  free  from  acid; 
if  any  matter  is  left  undissolved,  it  should  be  filtered  off  and  exam- 
ined.   A  few  drops  of  phenolphthalein  solution  are  then  added,  and, 
