86 
rochleder's  proximate  analysis. 
resinous  mass  is  divided  into  two  parts.  A  second  portion  of  the  resioous 
mixture  is  dissolved  in  spirit,  when  the  method  named  effects  no  separation. 
But  when  a  separation  has  been  thereby  effected,  the  part  soluble  in  am- 
monia is  dissolved  in  spirit.  The  spirituous  solutions  are  mixed  with  a 
solution  of  acetate  of  copper,  whereby  some  resins,  but  not  all,  are  preci- 
pitated. A  third  portion  of  the  resinous  mixture  is  treated  with  ether,  to 
effect,  if  possible,  a  separation.  Both  portions  of  resin  which  have  been 
separated  from  one  another  by  ammoniacal  water  are  treated  with  ether, 
to  produce  a  further  separation.  A  fourth  greater  quantity  of  the  resinous 
mixture  is  treated  in  the  following  manner  : — The  mixture  is  dissolved  in 
spirit,  and  the  solution  precipitated  with  a  spirituous  solution  of  acetate  of 
lead  as  long  as  a  precipitate  results.  The  fluid  is  separated  from  the  pre- 
cipitate by  a  filter,  and  this  is  washed  on  the  filter  with  spirit.  The  washed 
precipitate  is  diffused  in  spirit,  and  a  current  of  sulphuretted  hydrogen  is 
passed  into  the  fluid,  which  is  made  hot  by  surrounding  the  vessel  in  which 
it  is  placed  with  hot  water.  After  its  complete  decomposition,  the  solu- 
tion is  filtered  hot  from  the  sulphuret  of  lead  in  a  water  bath  funnel.  By 
the  cooling  of  the  filtrate  the  bulk  of  the  substance  separates  which  was 
previously  combined  with  the  lead.  A  portion  often  remains  dissolved, 
which  may  be  procured  by  evaporation.  Frequently  in  this  way  crystal- 
line waxy  compounds  are  obtained  by  cooling  separated  from  the  resins, 
while  sometimes  one  resin  or  the  other  remains  dissolved  in  the  fluid.  The 
fluid  which  is  filtered  from  the  precipitate  which  has  been  produced  by  the 
spirituous  solution  of  acetate  of  lead,  in  the  spirituous  solution  of  the 
resinous  mixture,  is  treated  with  sulphuretted  hydrogen.  The  lead,  as 
well  as  the  chlorophyll  when  present,  are  thereby  precipitated  from  the 
fluid.  The  sulphuret  of  lead  is  separated  by  filtration,  and  the  spirit  of 
the  solution  by  distillation,  whereby  the  resins  are  precipitated.  For  the 
prevention  of  any  alteration  by  heat,  the  distillation  is  undertaken  in  a 
water  bath.  The  resins  thereby  obtained  are  treated  with  a  weak  solution 
of  caustic  potash,  which  separates  the  soluble  from  the  insoluble  part.  The 
resulting  solution  is  mixed  with  a  watery  solution  of  chloride  of  calcium, 
the  resulting  precipitate  washed  on  a  filter,  and  then  dried  by  a  gentle 
heat  or  in  vacuo.  The  filtered  fluid  is  mixed  with  hydrochloric  acid,  where- 
by a  precipitate  frequently  makes  its  appearance,  which  is  collected  on  a 
filter,  washed  with  water,  and  then  dissolved  in  lime  water.  A  current  of 
carbonic  acid  gas  is  conducted  into  the  solution,  by  which  a  precipitation 
of  organic  substances  often  appears,  which  are  separated  from  the  combina- 
tions with  lime  by  the  carbonic  acid.  As  this  precipitate  is  contaminated 
with  carbonate  of  lime,  the  salt  is  extracted  with  dilute  hydrochloric  acid, 
or  the  organic  substances  are  separated  from  the  lime  salt  by  alcohol.  The 
fluid  filtered  from  the  carbonate  of  lime  and  the  organic  substances  is  heated 
for  the  decomposition  of  the  bicarbonate  of  lime  present.  The  fluid  is  again 
filtered,  and,  when  cold^  treated  with  dilute  hydrochloric  acid,  by  which  a 
