226 
Constituents  of  Yerba  Santa. 
( Am.  Jour.  Pharm. 
\       May,  1887. 
When  the  residuary  leaves  in  the  percolator  are  treated  with  water 
rendered  strongly  alkaline  with  ammonia,  the  first  portion  of  the  new 
percolate  is  very  turbid,  but  becomes  clear  as  the  free  ammonia 
descends  into  the  precipitate.  A  considerable  proportion  of  alkaline 
menstruum  is  needed  to  extract  the  color-giving  substance  wholly. 
Evaporation  of  the  percolate  to  a  syrupy  residue  and  treatment  of  this 
with  alcohol,  yields  a  brown  red  bitter  solution,  and  a  profuse  dark 
brown  precipitate.  The  solution  and  precipitate  are  in  all  respects 
identical  to  those  obtained  in  the  first  percolation.  The  alcoholic  solu- 
tion contains  the  quinine  precipitant  in  union  with  ammonia  as  an 
acidic  salt.  The  addition  of  water  causes  a  dense  milkiness,  and  acid- 
ulation  with  a  strong  acid  precipitates  the  acidic  resin  in  curdy  flakes. 
Excess  of  ammonia  added  to  the  alcoholic  solution  causes  no  precipi- 
tate, but  the  color  is  very  perceptibly  deepened.  On  exposure  of  this 
mixture  the  excess  of  ammonia  and  much  of  the  alcohol  is  dissipated, 
whilst  a  red-brown  tarry  acidic  ammonium  salt  deposits. 
The  precipitate  given  by  alcohol  appears  to  be  an  acidic  ammonium 
salt  of  the  tasteless  and  non-quinine  precipitating  acidic  component  of  the 
leaves.  When  treated  with  water  an  inconsiderable  proportion  dissolves, 
leaving  a  large  residue.  Addition  of  ammonia  or  potassium  carbonate  and 
much  water  dissolves  this  wholly  to  a  deep  red-brown  solution.  The 
tinctorial  power  of  this  body  is  its  most  remarkable  property.  In  its 
natural  condition  it  is  very  probably  in  great  part  an  acidic  anhydrate, 
which  is  dissolved  by  aqueous  solutions  of  alkalis  and  their  carbonates. 
Under  these  circumstances  no  perceptible  effervescence  occurs,  when 
carbonates  are  employed.  With  the  use  of  monocarbonates  the  solu- 
tion contains  bicarbonate,  showing  that  the  reaction  is  like  to  that 
resulting  in  similar  cases  with  analogous  matter  from  other  plants.  On 
adding  ferric  chloride  to  such  a  solution,  no  precipitate  at  first  appears. 
The  continued  addition  of  it,  however,  causes  an  abundant  brown-black 
precipitate  soluble  to  a  great  extent  in  an  excess  of  the  reagent.  It  is 
also  partially  soluble  in  ammonia  with  a  deep  red-brown  color.  The ' 
addition  of  ammonia  to  a  mixture  containing  excess  of  ferric  chloride 
gives  a  precipitate  utterly  insoluble  in  ammonia.  These  results  show 
that  the  various  proportions  of  the  tinctorial  body  appended  to  basic 
radicles  determine  the  degree  of  solubility  and  insolubility  of  the  com- 
pound. As  already  stated,  strong  acids  occasion  a  precipitate  when 
added  to  alkaline  solutions  of  this  substance.  Boiling  of  the  mixture 
with  dilute  sulphuric  acid  appears  to  generate  a  new  insoluble  sub- 
