332 
ON  OTTO  OF  ROSE. 
yellow  substance  soluble  in  ether,  and  the  reddish-brown  body 
soluble  in  alcohol. 
That  part  of  the  extract  insoluble  in  water  and  containing  the 
colocynthitin,  consists,  besides  this,  of  coloring  matter,  the  sub- 
stance soluble  in  ether,  and  the  one  soluble  in  alcohol. 
The  aqueous  solution,  after  the  precipitation  of  colocynthin  by 
tannin,  on  evaporation  to  one-half  and  neutralization  with  car- 
bonate of  soda,  yields  by  tannin  more  colocynthin,  to  which 
much  of  the  substance  soluble  in  ether  adheres.  The  filtrate, 
after  precipitating  with  subacetate  of  lead  and  neutralizing  with 
soda,  yields  another  precipitate  of  colocynthin  by  tannin. 
The  exhausted  colocynth  imparts  to  boiling  water  much  mucil- 
age, which  is  precipitated  by  alcohol ;  the  filtrate,  if  treated  as 
above,  yields  another  not  inconsiderable  quantity  of  colocynthin. 
Pure  colocynthin  has  the  composition  Or6  H42  023;  its  aqueous 
solution  is  decomposed  by  sulphuric  acid,  yielding  sugar  and 
colocynthein,  a  resinous  body,  soluble  in  ether.  C56  H42  023  -f 
2  HO  yield  C12  H12  012  +  044  H32  013  (colocynthein.) —  Wittstein's 
Viert.  Schrift.  vii.  558—565.  J.  M.  M. 
ON  OTTO  OF  ROSE. 
By  Daniel  Hanbury,  F.  L.  S. 
The  importance  of  authentic  specimens  is  well  understood  by 
naturalists.  The  botanist  who  has  had  the  opportunity  of  veri- 
fying the  Linnsean  name  of  a  plant  by  comparing  it  with  Linnse- 
us's  own  specimen,  is  sensible  that  no  more  satisfactory  proof  is 
wanting.  The  entomologist  who  can  appeal  to  the  specimens 
of  Fabricius,  or  the  zoologist  who  can  point  to  those  named  by 
Cuvier,  as  identical  with  his  own,  feels  that  he  can  rightfully 
adopt  the  names  given  by  those  authors.  Nor  is  the  student  of 
Materia  Medica  much  less  in  need  of  authentic  or  type  speci- 
mens as  standards  of  comparison.  Yet  how  difficult  it  would  be 
to  point  to  a  specimen  of  Sarsaparilla  as  indubitably  the  root  of 
one  particular  species  of  Smilax,  or  to  find  in  our  museums  a 
specimen  of  Myrrh  or  Olibanum,  or  Gamboge,  with  indisputable 
data  as  to  its  botanical  origin  and  place  of  production. 
These  observations  have  been  suggested  by  the  difficulty  which 
