348 
Fads  Concerning  Filtration. 
r  Am.  Jour,  Pharm. 
\      July,  1883. 
until  15  parts  are  left  which  dissolve  in  85  p.  of  flexible  collodion.  U. 
8. — Macerate  cantharides  50  p.  with  ether  80  p.  for  three  days,  strain, 
wash  the  residue  with  sufficient  ether  to  obtain  42  parts  of  filtrate ;  to 
this  add  collodium  cotton  2  parts,  alcohol  6  parts.  P.  G. — Appa- 
rently the  latter  preparation  is  of  nearly  double  the  strength  of  the 
former;  but  when  it  is  observed  that  fully  one-half  the  etherial  liquid 
is  wasted  by  being  retained  in  the  powdered  cantharides,  it  must  ob- 
viously be  somewhat  weaker  than  that  of  the  U.  S.  P. 
Collodium  flexile^  U.  S.  Collodium  elasticura,  P.  G.-  —Collodion  92 
p.,  Canada  turpentine  5  p.,  castor  oil  3  parts  U.  S. — Collodion  98  p., 
castor  oil  2  parts  P.  G. 
Confedio  Sennce,  U.  S.  Electuarium  e  Senna,  P.  G. — The  pulpy 
liquid  obtained  with  water  from  cassia  fistula  16  p.,  tamarind  10  p., 
prune  7  p.  and  fig  12  p.,  is  mixed  with  sugar  50  parts  and  evaporated 
to  84  parts;  mix  this  with  powdered  senna  10  p.  and  coriander  6  parts. 
U.  S. — Mix  powdered  senna  10  p.,  simple  syrup  40  p.,  and  pulp  of 
tamarind  50  j^arts.  P.  G. 
Decodmn  Sarsajmrilke  compositum.  The  German  Pharmacopoeia 
recognizes  a  strong  and  a  weak  decoction,  which  resemble  the  formerly 
much  used  Zittmann's  decoctions  witliout  the  use  of  vermilion  and 
calomel;  the  present  formula  is  a  slight  modification  of  that  contained 
in  P.  G.  edit.  1. 
SOME  FACTS  CONCERNING  FILTRATION. 
By  Charles  Symes.^ 
The  process  of  percolation  has  engaged  so  much  attention  of  late 
years  that  it  is  not  surprising  to  find  the  less  important,  although 
kindred  one,  filtration,  somewhat  neglected.  It  may  be  thought  that 
all  has  been  accomplished  that  could  reasonably  be  desired  for  render- 
ing this  operation  as  complete  as  it  can  be,  or  that  it  is  too  simple  to 
merit  much  consideration.  Be  this  as  it  may,  practical  pharmacists 
know  quite  well  that  they  are  not  unfrequently  troubled  to  conduct  it 
to  their  entire  satisfaction. 
The  more  serious  difficulties  connected  therewith  do  not  perhaps 
occur  to  each  individual  very  often,  hence  the  danger  that  the  experi- 
ence grained  on  one  occasion  is  overlooked  or  not  made  available  when 
circumstances  again  arise  for  its  application. 
^  Read  before  the  Liverpool  Chemists'  Association. 
