Am.  Jour.  Pharm.  \ 
August,  1894.  J 
Pharmaceutical  Notes. 
393 
magnifying  four  diameters  (it  is  stated  that  the  shaking  can  be  best 
done  by  mechanical  means). 
This  no  doubt  is  true. 
It  is  finally  to  be  mixed  with  the  prepared  chalk,  brought  to  a 
creamy  mixture  with  water  in  a  mortar,  until  thoroughly  extin- 
guished, then  dried  and  powdered  without  trituration. 
This  process  was  submitted  last  winter  to  my  laboratory  (senior) 
class  and  proved  a  failure  even  after  careful  and  hard  work  and 
repeated  attempts.  It  may  be  possible  to  make  it  work  by  mechan- 
ical contrivances  on  a  large  scale,  but  is  certainly  not  well  adapted 
to  the  wants  of  the  retail  pharmacist. 
An  improvement  is  needed. 
Liquor  Magnesii  Citratis. 
The  formula  generally  is  good,  but  why  use  120  cc.  of  syrup 
of  citric  acid  to  a  bottle  ?  This  is  too  much  and  must  be  too 
sweet  for  most  people.  60  cc.  has  always  been  considered  very 
palatable. 
Mangani  Dioxidum. 
Attention  has  been  drawn  to  the  fact  that  when  this  chemical 
compound  is  prescribed,  the  dispenser  should  be  particular  to 
employ  only  the  purified  substance. 
The  commercial  powder  usually  contains  about  66  per  cent,  of 
the  dioxide,  while  the  pure  is  claimed  to  contain  90  per  cent.,  and 
has  the  objectionable  contaminations  removed. 
The  pharmacopoeial  article  is  the  commercial,  but  the  purified 
substance  is  furnished  by  the  manufacturing  chemists  at,  of  course, 
a  much  higher  price,  but  well  worth  the  difference  from  the  stand- 
point of  the  careful  prescriptionist. 
Collodium  Cantharidatum. 
The  official  process  directs  to  exhaust  the  drug  in  No.  60  powder 
with  chloroform  by  percolation  (in  a  percolator  for  volatile  men- 
strua), recovering  the  chloroform  by  distillation  and  dissolving 
remaining  15  grams  of  oily  extract  in  85  grams  of  flexible 
collodion. 
I  prefer  and  have  for  some  time  used  the  following  method.  It 
somewhat  accelerates  and  cheapens  the  product : 
Exhaust  the  powdered  flies  with  ether  in  same  kind  of  percolator 
as  already  mentioned,  distill  off  ether  from  percolate  until  reduced 
to  70  parts;  add  3  parts  of  pyroxylin,  5  parts  Canada  turpentine,  3 
