272 
UNG.  HYDRARGYRI  NITR. 
Second  experiment : — 17  grammes  of  the  head  and  antenrise 
(there  were  very  few  antennae)  were  treated  with  35  grammes 
of  chloroform,  like  the  preceding,  and  from  them  0-015  of  can- 
tharidin  was  obtained. 
Third  experiment : — 11  grammes  of  the  elytra  and  membran- 
ous wings  were  treated  with  25  grammes  of  chloroform,  and 
yielded  0-009  of  cantharidin. 
Fourth  experiment : — 30  grammes  of  the  thorax  and  abdomen 
were  mixed  in  a  displacement  apparatus  with  70  grammes  of 
chloroform.  In  this  experiment  the  residue  obtained  by  the 
spontaneous  evaporation  of  the  chloroform,  furnished  a  large 
quantity  of  crystals.  After  having  absorbed  the  oil  and  redis- 
solved  the  crystals  in  a  small  quantity  of  chloroform,  I  threw 
the  solution  on  a  filter.  After  filtration  I  opened  the  paper  and 
found  it  covered  with  small  micaceous  crystals  of  cantharidin 
perfectly  white.  The  chloroform  had  deposited  the  crystals  as 
it  evaporated,  and  the  green  oil  had  passed  through  with  the 
chloroform  which  had  not  evaporated.  As  this  last  portion 
might  still  contain  a  small  quantity  of  cantharidin,  I  evaporated 
and  again  dissolved  it  in  a  little  chloroform,  and  threw  it  on  a 
filter  as  before.  After  repeating  this  a  third  time  I  obtained 
all  the  cantharidin  furnished  by  the  30  grammes  of  the  thorax 
and  abdomen  perfectly  white.    It  weighed  0-072  grammes. 
The  blisters  produced  on  my  arm  by  a  very  small  quantity 
of  the  crystals  obtained  in  my  experiments,  left  no  doubt  of 
their  nature.  From  these  experiments  the  author  draws  the 
conclusion  that  the  active  principle  of  cantharides  is  found  dis- 
tributed over  all  parts  of  the  body  Ohem.  News,  Jan.  21,*  from 
Rep.  dePharm. 
ON  THE  PREPARATION  OF  THE  UNGUENTUM  HYDRARGYRI 
NITRATIS,  (PH.  L.) 
»      By  Julius  Schweitzer. 
No  preparation  of  the  London  Pharmacopoeia  is  more  difficult 
to  obtain  of  a  constant  and  uniform  appearance  and  consistence 
*Dr.  Leidy  (see  page  157  of  this  volume,)  shows  that  cantharidin  exists  in 
the  blood  of  the  insect  and  in  certain  organs  near  the  generative  organs,-— 
Ed.  Am.  Jour.  Pharm. 
