250  Philadelphia  College  of  Pharmacy.  \Am-^'i9w.Tm' 
years  old,  and  that  it  is  still  of  good  quality  both  as  regards  flavor 
and  odor. 
William  G.  Toplis,  Ph.G.,  presented  a  paper  on  "  Rapid  Sand 
Filtration  Compared  to  Slow  Sand  Filtration"  (see  p.  227)  and 
in  this  connection  exhibited  a  model  of  a  "  sand  valve,''  and  demon- 
strated the  chemical  process  involved  in  the  purification  of  water 
by  the  use  of  alum.  To  show  the  practical  efficiency  of  rapid  sand 
filtration,  Mr.  Toplis  also  read  a  report  on  a  bacteriological  and 
chemical  investigation  which  he  had  made  of  the  operation  of  the 
filter  plant  recently  installed  at  Plattsburg  Barracks,  N.  Y.,  by 
Hungerford  &  Terry,  Inc.,  of  Philadelphia. 
Mr.  Cliffe  stated  that  in  making  milk  of  magnesia  with  the 
filtered  water  of  either  the  Delaware  or  Schuylkill  River,  which 
is  ordinarily  clear,  the  preparation  has  a  yellow  color,  and  that  the 
use  of  distilled  water  made  the  process  an  expensive  one  for  the 
retail  pharmacist.  He  then  inquired  of  Mr.  Toplis  whether  in  his 
opinion  the  entire  process  outlined  by  him  would  render  the  water  of 
such  a  degree  of  purity  as  to  fit  it  for  use  in  the  making  of  milk 
of  magnesia,  which  question  Mr.  Toplis  answered  in  the  affirmative. 
Otto  W.  Osterlund,  P.D.,  spoke  of  the  same  difficulty,  and  stated 
that  he  had  found  it  advisable  to  abandon  the  manufacture  of  milk 
of  magnesia. 
Mr.  Beringer  stated  that  he  makes  hydrated  oxide  of  bismuth 
by  an  inverted  percolation  process,  which  he  said  is  in  reality  a 
process  of  dialysis.  He  remarked  on  the  difficulty  of  removing  the 
ammonia  in  the  magma  by  decantation,  stating  that  much  less  water 
is  required  by  his  process  than  in  the  official  method,  and  that  a 
constant  layer  of  water  can  be  kept  above  the  magma  until  the 
process  is  completed  by  use  of  the  dropping  bottle.  He  stated,  also, 
that  he  obviates  the  undue  expense  connected  with  the  manufacture 
of  this  preparation  by  manufacturing  his  own  distilled  water.  For  the 
clarification  of  tap  water  he  suggested  the  use  of  magnesium  carbon- 
ate or  light  calcined  magnesia  as  a  filtering  medium,  and  stated  that 
sometimes  the  cloudy  appearance  of  the  tap  water  is  due  to  a  dis- 
turbance of  the  lining  of  the  pipes.  The  speaker  also  pointed  out 
that  in  the  chemical  examination  of  water,  it.  is  desirable  for  the 
chemist  to  have  a  knowledge  of  the  chemical  purification  undergone 
bv  the  water,  as,  otherwise,  supposedly  objectionable  elements,  such 
as  chlorine,  resulting  from  the  purification,  would  be  considered 
natural  deleterious  ingredients. 
