16  Notes  on  Tincture  of  Quillaia.  {^""'jan.^ilS^''"'' 
an  increasing  demand  for  tincture  of  quillaia  for  internal  use ;  in 
Edinburgh  this  has  been  markedly  so  since  the  beginning  of  this  year, 
when  Dr.  Claud  Muirhead,  in  the  Edinburgh  Medical  Journal,  re- 
ferred in  commendatory  terms  to  the  administration  of  the  drug  in 
bronchitis,  and  there  is  just  a  possibility  that  the  B.P.C.  formula  may 
be  taken  as  a  guide  to  the  preparation  of  the  tincture  for  this  purpose. 
It  would,  I  think,  be  a  pity  if  it  were  so  taken,  because  this  tincture 
does  not  at  all  represent  the  virtues  of  the  bark.  I  have  looked  up  a 
number  of  references  to  quillaia,  and  I  find  that  all  the  writers  on 
the  subject  agree  in  the  conclusion  that  water  is  the  best  solvent  of  sa- 
ponin, which  is  regarded  as  the  active  principle  of  the  bark.  Gmelin 
says  that  saponin  is  easily  soluble  in  water  (1  in  4),  more  soluble  in 
dilute  than  strong  alcohol,  insoluble  in  absolute  alcohol. 
Hager  gives  a  formula  of  an  infusion,  and  a  tincture  prepared  with 
dilute  alcohol. 
Grazer,  an  American  pharmacist,  recommends  for  emulsifying  pur- 
poses a  tincture  with  3  parts  of  water  and  8  of  rectified  sj3irit. 
Dr.  Claud  Muirhead  has  used  with  success  a  decoction. 
Collier  gives  a  formula  (Phar.  Jour.,  Sep.  20, 1879,  Am.  Jour.  Phar., 
1880,  41)  for  emulsifying  purposes  with  4  ounces  of  bark  to  a  pint  of 
rectified  spirit ;  this  apparently  is  the  formula  copied  into  the  B.P.C. 
formulary,  but  made  with  only  half  the  quantity  of  bark. 
For  the  purposes  of  this  note  I  have  prepared  tinctures  of  vari- 
ous alcoholic  strengths.    I  take  three  of  these  for  comparison  : 
'No.  1  is  made  according  to  the  B.P.C.  formula. 
No.  2  is  made  with  proof  spirit. 
No.  3  is  made  with  3  of  rectified  spirit  and  4  of  water. 
The  time  at  my  disposal  since  agreeing  to  bring  the  subject  before 
this  meeting  has  not  been  sufficient  to  enable  me  to  estimate  the  com- 
parative values  of  these  tinctures  except  in  a  somewhat  rough  and 
ready  way,  although  I  believe  the  results  may  be  taken  to  be  fairly 
trustworthy.  The  quantity  of  saponin  in  a  tincture  may  be  estimated 
comparatively  by  the  amount  of  froth  which  it  produces  when  shaken 
up  with  a  quantity  of  water.  Taking  the  three  tinctures  above  men- 
tioned, adding  one-half  a  drachm  of  each  to  two  ounces  of  water  in  a 
six-ounce  bottle,  and  shaking,  the  following  results  were  observed : 
No.  1  gave  of  froth  1. 
No.  2         "    "  If. 
No.  3    "  "  2. 
