320  PHARMACEUTICAL  GLEANINGS  AND  NOTICES. 
choice  of  a  process  will  depend,  in  some  mea3ure,  upon  the 
composition  of  the  pills,  and  other  circumstances  which  it  is 
difficult  to  foresee.  The  processes,  No.  29  (rolling  in  tincture 
of  lac,  and  in  equal  parts  of  resin  and  French  chalk  powders,) 
and  No.  45,  (rolling  in  a  mixed  tincture  of  3ss.  of  lac  and  ~i. 
of  resin  in  fgiiiss.  of  spirit,  and  then  in  a  mixture  of  three 
parts  French  chalk  and  one  part  resin,)  are  those  which  appear 
to  promise  the  most  general  utility.  The  proportion  between 
the  quantity  of  the  tincture  and  the  number  of  the  pills  con- 
siderably influences  the  quality  of  the  coat.  For  dispensing 
purposes  it  is  convenient  to  use  a  two  or  three  ounce  pomatum 
pot,  into  which  the  tincture  is  dropped  in  about  the  proportions 
of  four  or  five  minims  to  a  dozen  pills,  diminishing  the  quantity 
for  large  numbers,  then  putting  in  the  pills,  and  shaking  them 
till  uniformly  covered,  after  which  they  may  be  immediately 
thrown  into  a  tray  sufficiently  large  to  allow  of  their  rolling 
freely ;  when  covered  with  the  powder,  they  may  be  at 
once  transferred  to  the  box,  but  when  occasion  permits,  it  is 
advantageous  that  a  few  minutes  be  allowed  for  the  hardening 
of  the  varnish. 
Vesicating  Collodion. — Mr.  Charles  R.  C.  Tichborne,  in  the 
London  Pharmaceutical  Journal  for  April,  1862,  discusses  the 
subject  of  vesicating  collodion,  and  offers  a  formula  which  he 
considers  effective  and  worthy  of  adoption,  as  uniform  and 
reliable  in  its  action.  The  author  remarks  on  the  variable 
character  of  vesicating  collodion  as  dispensed  in  London,  owing 
to  the  fact  that  pharmaceutists  have  private  formulae  differing 
from  each  other.  Mr.  T.  thinks,  in  this  preparation,  the  collo- 
dion should  be  associated  with  some  substance  like  acetic  acid, 
that  will  render  it  permeable  by  the  active  principle,  which  he 
esteems  is  not  the  case  with  collodion,  basing  his  arguments  on 
the  conditions  presented  by  a  film  of  simple  collodion  on 
glass,  which  he  examines.  Now  it  is  probable  that  vesicating 
collodion  has  been  more  used  in  the  United  States  than  else- 
where, mainly  owing  to  the  lower  price  of  the  vehicle ;  and  the 
experience  of  American  Pharmaceutists  shows,  that,  if  well 
made,  the  quantity  of  fixed  oil  which  is  withdrawn  from  the 
