486 
Pharmazeutischen  Institut. 
/Am.  Jour.  Pharm. 
\    October,  1910. 
of  the  difficulties  involved  in  the  production  of  these  preparations. 
In  common  with  other  observers  he  notes  that  the  complete 
exhaustion  of  a  drug  requires  from  5  to  8  times  the  weight  of  the 
drug  itself.  He  also  discusses  the  economic  questions  that  are 
involved  in  the  production  of  rluidextracts  by  manufacturers,  the 
variation  in  the  price  of  the  preparations,  and  presents  a  table 
giving  the  results  of  his  observations  on  a  number  of  commercial 
preparations  and  an  equal  number  made  in  the  laboratory  of  the 
hospital  with  which  he  is  connected  (Apoth.  Ztg.,  Berlin,  1910, 
v.  25,  pp.  522-523). 
Melting  Point  Determination. — L.  Derlin  recommends  the 
metallic  bath  as  being  the  most  satisfactory  for  determining  the 
melting  point  of  most  organic  chemicals  used  in  pharmacy.  For 
substances  that  melt  at  higher  temperatures  the  figures  are  usually 
low  (Apotheker  Ztg.,  1910,  v.  25,  p.  435). 
Richter  Ernst,  in  discussing  the  value  of  melting  point  de- 
terminations, points  out  the  advantage  of  the  apparatus  figured  in 
"  Vierteljahresschrift  fur  praktische  Pharmazie,  1907,  p.  145.  This 
apparatus  has  the  advantage  that  the  sulphuric  acid  circulates  and 
heats  evenly  so  that  the  apparatus  can  be  allowed  to  stand  without 
further  care.  To  prevent  the  destruction  of  the  cork  he  recom- 
mends coating  it  with  collodion  {Apotheker  Ztg.,  1910,  v.  25, 
p.  476). 
Refractometer. — The  Chemist  and  Druggist,  July  16,  1910, 
p.  51,  points  out  that  the  next  edition  of  the  British  Pharmacopceia 
will  probably  provide  refractive  indices  for  oils  and  other  liquids 
the  quality  of  which  may  be  determined  by  examination  with  the 
refractometer,  an  instrument  whose  value  in  the  examination  of 
essential  oils  is  well  established.  The  article  includes  a  description 
and  illustration  of  the  refractometer  generally  used. 
ARBEITEN  AUS  DEM  PHARMAZEUTISCHEN  INSTITUT 
DER  UNIVERSITAT  BERLIN. 
Of  the  large  number  of  papers  appearing  in  the  annual  publication 
of  the  work  done  at  the  Pharmaceutical  Institute  of  the  University 
of  Berlin,  none  are  so  important  and  of  such  practical  value  as  those 
which  reveal  to  physicians  and  pharmacists  the  false  and  misleading 
claims,  to  say  nothing  of  downright  sophistication,  made  in  the 
