AmDec.?i89oarm"}  Gleanings  from  the  German  Journals.  613 
attention  to  the  fact  that  only  decolorized  glycerins  (not  purified  by 
distillation)  will  comply  with  the  pharmacopceial  test ;  these  glycer- 
ins contain  most  of  the  impurities  of  the  crude  glycerin.  After  this 
discovery,  to  samples  of  distilled  glycerin  were  added  several  per 
cent,  of  arsenious  oxide,  and  these  samples  then  submitted  to  the  test ; 
it  was  found  that  they  complied  with  the  test  and,  hence,  the  deduction 
that  the  test  is  of  no  service  in  the  detection  "of  arsenic  in  glycerin- 
The  cause  of  this  is  ascribed  to  the  use  of  such  a  large  excess  of 
ammonia,  Dr.  Jaffe  stating  that  with'a  large  excess  of  ammonia  all 
samples  of  glycerin  will  fail  to  show  any  reduction,  while  if  an 
excess  of  glycerin  be  used,  all  samples  will  reduce  ammoniacal  silver 
nitrate ;  as  long  as  by  the  presence  of  a  sufficient  quantity  of  ammo- 
nia the  boiling  point  of  the  mixture  be  kept  sufficiently  low,  no 
reduction  will  take  place ;  if,  by  boiling,  a  portion  of  the  ammonia 
be  vaporized  the  boiling  point  rises,  finally  reaching  such  a  temper- 
ature at  which  reduction  will  take  place  under  all  conditions.  Using 
a  sufficient  excess  of  ammonia,  formic  acid,  arsenious  acid  and  alde- 
hyde will  also  fail  to  reduce  silver  nitrate — Chemiker  Ztg.,  1890, 
1,493- 
Morphine  salts  and  cherry-laurel  water. — The  appearance  of  a 
precipitate  in  a  freshly-made  solution  of  morphine  hydrochlorate  in 
distilled  cherry-laurel  or  bitter  almond  water  has  been  frequently 
noticed;  the  precipitation  has  been  explained  in  various  ways  :  (1) 
Decomposition  of  the  solution  by  light  ;  (2)  by  the  glass  vessels  giv- 
ing up  alkali  to  the  solution  ;  (3)  by  action  of  micro-organisms,  and 
(4  )  by  the  use  of  magnesia  in  making  the  medicinal  water  (Am. 
Journ.  Pharm.,  1890,  163).  Theodor  Salzer  recently  found  the  pre- 
cipitation in  one  case  at  least  to  be  due  to  the  distilled  bitter  almond 
water  containing  considerable  quantities  of  ammonium  cyanide,  a 
constituent  of  the  bitter  almond  water  first  noticed  by  Linde.  Salzer 
found  10  cc.  of  the  water  to  contain  sufficient  of  this  normal  consti- 
tuent to  precipitate  0-4  gram  morphine.  The  water  used  in  making 
this  bitter  almond  water  was  free  from  ammonia. — Pliarm.  Ztg.. 
1890,  669. 
Caoutchouc  solutions  may  be  readily  made  by  adding  to  the  sol- 
vents, benzol,  carbon  disulphide,  etc.,  certain  volatile  oils,  especially 
eucalyptus  oil.  Mixtures  containing  96  to  92  parts  benzol  and  4  to 
8  parts  eucalyptus  oil,  or  95  parts  carbon  disulphide  and  15  parts 
eucalyptus  oil  will  easily  dissolve  16  to  20  parts  of  caoutchouc.  *  It 
