544  Britiy:  Pharmaceutical  Conference.  {Am*^iSafm 
conjoined  with  the  great  I'L.iculty  experienced  in  detecting  hydrocyanic  acid 
in  bodies  long  after  death,  should  induce  toxicologists  to  give  it  a  trial. 
The  adjournment  for  lunch  at  the  Waterloo  Hotel  then  took  place  as  on  the 
previous  da}^,  and  on  reassembling  the  following  papers  were  read  : 
Quinine  Phosphate. — Mr.  George  Coull  has  recently  investigated  the  com- 
position of  quinine  phospaate  and  finds  that  there  are  at  least  two  phosphates. 
He  suggests  that,  in  view  of  the  practical  importance  of  a  difference  in  the 
percentage  of  alkaloid,  it  would  be  advantageous  that  a  salt  having  a  definite 
formula  should  be  specified  in  the  B.  P.  C.  Formulary.  Barium  hypophosphite 
is  another  compound  in  which  Mr.  Coull  has  found  considerable  variation,  and 
he  recommends  that  the  anhydrous  salt  be  used  and  the  standard  of  purity 
raised.  In  phosphoric  acid,  too,  he  has  found  silica  present,  and  a  simple  test 
is  suggested  for  its  detection. 
Cacao  Butter.— The  record  of  Mr.  T.  Maltby  Clague's  investigation  into  the 
melting  point  of  cacao  butter  affords  a  remarkable  instance  of  the  manner  in 
which  variation  in  the  behavior  of  different  samples  of  a  similar  substance  ma}' 
often  be  explained  by  purely  physical  causes.  Indeed,  his  experiments  go  far 
to  prove  that  this  substance  may  have  its  characteristics  considerably  influ- 
enced and  even  permanently  altered  by  a  temporary  subjection  to  changes  in 
its  surroundings.  In  ten  commercial  samples  of  cacao  butter  he  found  the 
melting  point  varied  from  730  to  910  F.  The  B.  P.  range  is  from  S63  to  95°. 
A  sample  expressed  by  Mr.  Clague  from  the  nibs  with  the  aid  of  heat  melted 
at  91°,  another  obtained  by  percolation  with  ether,  at  S30,  whilst  a  third 
extracted  in  the  same  way  from  a  prepared  cocoa  had  a  melting  point  at  96'. 
Certain  of  the  commercial  specimens  were  further  treated  by  being  heated 
consecutively  to  1050,  1200,  1500  and  1800  F.  The  melting  point  in  each  case 
altered  considerably  under  this  treatment,  for,  being  ascertained  after  each 
step,  it  was  found  to  rise  until  it  reached  an  apparent  maximum,  after  which 
any  further  increase  of  temperature  lowered  it  again.  Maintaining  an 
increased  temperature  for  a  length  of  time  was  also  found  to  exert  a  dis- 
tinct influence,  a  sample  with  a  melting  point  of  75°  F.  having  this  raised  to 
86°,  after  being  kept  at  a  temperature  just  under  iooc  for  two  hours.  It 
appears  evident  that  such  variability  in  the  commercial  product  is  the  result 
of  the  application  of  heat  in  greater  or  less  degree  during  the  process  of 
extraction ;  for  a  specimen  prepared  by  percolation  with  ether  from  its 
unroasted  nibs  possessed  a  practically  constant  melting  point  of  86°  F.  Mr. 
Clague  inclines  to  the  opinion  that  a  complete  solution  of  the  difficulty  will 
only  be  obtained  after  a  chemical  investigation,  and  meanwhile  he  warns  dis- 
pensers to  exercise  care  in  the  selection  of  cacao  butter  suitable  as  a  basis  in 
suppository  making. 
At  the  conclusion  of  this  paper  Mr.  Clague  made  some  remarks  on  the 
methods  of  taking  melting  points. 
Tincture  of  Cinchona  — Messrs.  E.  H.  Farr  and  R.  Wright,  continuing  their 
investigations  on  tincture  menstrua,  gave  particulars  of  their  experiments  with 
tincture  of  cinchona,  and  the  results  appear  to  indicate  the  advantage  of  the 
official  macero-percolation  process  as  compared  with  other  methods  in  the 
preparation  of  this  galenical. 
Mr.  F.  C.  J.  Bird  described  a  novel  pressure  filter  oi  great  simplicity,  which 
he  has  found  of  value  in  making  determinations  by  Mayer's  method. 
