84 
rochleder's  proximate  analysis. 
spirit.  Generally  the  greater  part  remains  behind,  which  consists  of  albu- 
minous bodies  which  are  present  in  a  coagulated  condition,  or,  like  legumine, 
are  insoluble  in  a  free  condition  in  alcohol  and  water,  but  with  ammonia 
afford  compounds  soluble  in  water.  They  are  precipitated  from  their  so- 
lutions by  hydrochloric  acid,  and  remain  undissolved  by  the  treatment 
with  spirit.  Among  the  bodies  extracted  by  ammonia  and  precipitated  by 
hydrochloric  acid,  and  also  in  the  part  soluble  in  alcohol,  of  the  mixture 
thus  obtained,  substances  often  exist  which  are  extracted  by  alcohol  from 
the  material  under  examination,  because  they  are  not  soluble  in  pure  water, 
but  are  as  soluble  in  ammoniacal  water  as  in  spirit ;  for  example,  chinovic 
acid,  &c.  We  often  obtain  bodies  of  that  kind  purer  from  this  ammoniacal 
extract  than  from  a  spirituous  extract  of  the  material,  in  which  they  are 
accompanied  with  many  other  substances,  while  in  this  case  many  of  these 
substances  are  separated  for  the  most  part  by  the  previous  boiling  with  pure 
water,  and  thus  do  not  interfere  with  their  preparation  in  a  pure  state. 
It  often  happens  that  substances  combined  with  lime  or  magnesia  are  quite 
as  insoluble  in  water  and  spirit  as  in  ammoniacal  water.  When  the  sub- 
stance combined  with  lime  or  magnesia  is  insoluble  in  acididated  water,  it 
can  only  be  obtained  in  the  following  way  from  the  material : — A  portion 
of  the  material,  boiled  with  water,  is  extracted  with  water  containing  hy- 
drochloric acid,  whereby  the  lime  and  magnesia  compounds  in  question  are 
decomposed,  and  the  lime  and  magnesia  dissolved  as  chlorides  and  removed. 
All  that  is  soluble  is  separated  by  washing  with  pure  water,  and  then  the 
material  is  extracted  with  ammoniacal  water,  which  now  dissolves  the  or- 
ganic body  rendered  free,  which  was  insoluble  as  a  lime  or  magnesia  com- 
pound, and  may  be  precipitated  insoluble  in  water  upon  the  addition  of 
hydrochloric  acid.  By  the  decoction  of  the  material  with  spirit  containing 
sulphuric  acid,  after  it  has  been  already  exhausted  with  spirit,  these  bodies 
may  be  obtained  likewise  ;  but  we  are  in  danger,  by  the  action  of  the 
acid  in  the  heat,  of  producing  changes  in  the  bodies  we  desire  to  iso- 
late. 
V. — Examination  of  the  Spirituous  Extract  or  Decoction. 
a. — Deposits  from  the  spirituous  extract  or  decoction. 
From  the  spirituous  extract  of  the  substance  under  examination,  when 
the  extract  is  prepared  with  hot  alcohol,  bodies  are  deposited  sometimes 
by  its  cooling,  or  after  a  portion  of  the  spirit  has  been  distilled  off,  which 
must  be  subjected  to  a  closer  examination.  With  a  cold  prepared  infusion, 
deposits  of  that  kind  make  their  appearance  generally  after  the  distillation 
of  the  alcohol,  but  mostly  in  smaller  quantities.  Resins,  kinds  of  wax,  fats, 
with  other  peculiar  bodies  which  belong  to  none  of  these  classes — as,  for 
example,  saponine — are  contained  in  these  deposits,  which  frequently  ap- 
pear of  a  dark  green  color  like  the  spirituous  extract  itself,  when  vege- 
table substances  containing  chlorophyll  have  been  extracted  with  spirit. 
