154 
Salicylate  of  Atropia. 
{Am.  Jour.  Pbarm. 
April,  1677, 
If  the  atropia  and  salicylic  acid  be  mixed,  in  equivalent  propor- 
tions, and  water  added,  both  the  substances  dissolve  after  some  time, 
although  the  ingredients  are  both  comparatively  insoluble  in  cold  water. 
The  proportions  used  were,  atropia  289,  salicylic  acid  138  grains.  If 
the  aqueous  solution  be  evaporated,  a  colloidal  mass  will  be  obtained 
difficult  to  powder.  An  attempt  was  made  to  crystallize  the  salt  from 
ether,  but  without  success.  Alcohol  was  also  tried  with  a  like  result. 
This  difficulty,  as  regards  crystallization,  is  characteristic  of  the 
atropia  salts.  The  actual  solubility  of  this  salt  was  determined  at  a 
temperature  of  150  C.  In  two  determinations  it  gave,  as  regards 
saturated  solutions  : 
1st  determination,  .  .  .    4-76  per  cent.  salt. 
2d  "  ...  4-69 
Therefore,  if  we  call  this  47  per  cent.,  and  as  9i_3  =  20*2,  we  may 
47 
say  that  practically  salicylate  of  atropia  is  soluble  in  20  parts  of  cold 
water.  Therefore  it  is  evident  that  it  is  easy  to  prepare  a  solution  of 
salicylate  of  atropia  which  shall  represent  the  solutions  of  atropia  of  the 
"  Pharmacopoeia  "  by  dissolving  atropia  and  crystallized  salicylic  acid 
in  the  following  proportions  : 
Atropia,  .  .  .  .  .  •    ~"7  grains 
Salicylic  acid  |  crystallized),        .  .  .  13  " 
^  Water,  .  .  .  .  .1     ounc  ; 
Mix,  and  allow  it  to  stand  until  it  is  dissolved. 
With  care,  however,  the  salicylate  of  atropia  may  be  obtained  in 
the  solid  form,  and  then  resembles  the  sulphate  in  appearance.  In  the 
proportions  given  above  the  acid  is  slightly  in  excess  of  that  required 
by  theory.  It  is  found  desirable  to  have  a  slightly  acidulated  solution, 
or,  under  any  circumstances,  not  an  alkaline  one,  because  a  salicylate 
does  not  act  as  an  antiseptic  in  the  presence  of  an  excess  of  alkaloid,  or 
what  may  be  called  an  alkaline  solution.  A  solution  made  in  the  pro- 
portions given  above  will  keep  for  an  indefinite  time.  I  have  placed 
on  the  table  a  sample  of  the  solution  of  salicylate  of  atropia,  four  grains 
to  the  ounce.  It  was  made  on  August  4,  1876,  so  that  it  is  now  over 
six  months  old,  and  there  is  not  the  slightest  sign  of  any  fungoid 
growth.  As  regards  the  possibility  of  its  producing  irritating  effects, 
I  placed  some  of  this  solution  in  the  hands  of  friends  who  are  in  the 
foremost  ranks  as  regards  ophthalmic  surgery.     They  have,  with  their 
