ON  THE  LOCALITY  OF  CANTHARLDIN. 
271 
he  contended  that  the  soft  parts  of  all  regions  possessed  a  vesi- 
cating property  ;  that  the  soft  or  internal  parts  of  the  legs  and 
head  are  as  active  as  those  of  the  thorax  and  abdomen,  and  that 
the  only  parts  of  the  body  completely  inert  are  the  elytra,  the 
antennae,  and  the  portions  of  the  feet  composed  only  of  hard 
parts. 
In  1856,  M.  Berthoud  sought  chemically  for  cantharidin : 
1,  in  the  abdomen  and  thorax,  which  he  designated  the  soft  parts 
of  the  flies  ;  and  2,  in  the  elytra,  wings,  antennae,  and  feet, 
which  he  called  the  horny  parts  : 
250  grammes  of  the  abdomen  and  thorax  gave  045  of  can- 
tharidin. 
125  grammes  of  the  horny  parts  gave  0-053. 
These  results,  completely  opposed  to  the  conclusions  of  M. 
Farines,  do  not,  however,  demonstrate  the  existence  of  can- 
tharidin in  every  part  of  the  body  of  the  fly.  They  only  serve  to 
confirm  the  opinion  and  the  observations  of  M.  Courbon.  The 
parts  which  M.  Berthoud  has  named  collectively  the  horny 
parts,  and  from  which  he  has  extracted  the  cantharidin,  contain 
in  their  interior  a  certain  quantity  of  soft  parts  (the  soft  parts 
of  the  head  and  legs\  and  the  cantharidin  might  be  obtained 
exclusively  from  these  soft  parts  if  the  observations  of  M.  Cour- 
bon were  strictly  true. 
On  a  question  so  interesting  and  as  it  appeared  to  me  so  im- 
perfectly resolved,  I  thought  it  would  be  useful  to  make  some 
new  researches.  To  ascertain  whether  cantharidin  is  indiffer- 
ently distributed  over  every  part  of  the  body,  or  whether  it  is 
only  contained  in  particular  parts,  I  have  sought  for  it, — 1,  in 
the  feet  and  legs  ;  2,  in  the  head  ;  3,  in  the  elytra  and  wings ; 
and  4,  in  the  thorax  and  abdomen. 
First  experiment : — 11  grammes  of  the  feet  and  legs  were 
powdered  and  treated  in  a  displacement  apparatus  with  25 
grammes  of  chloroform  ;  after  macerating  for  three  days  the 
liquid  was  run  off  and  the  chloroform  displaced  by  means  of 
alcohol.  The  chloroform  so  obtained  was  allowed  to  evaporate 
in  the  air,  and  the  residue  was  placed  between  folds  of  blotting 
paper  to  absorb  the  oil.  The  crystals  left  were  redissolved  in  a 
small  quantity  of  chloroform,  again  crystallized  and  then  weighed. 
From  the  11  grammes  of  the  feet,  0*01  of  cantharidin  was  ob- 
tained, still  stained  with  a  little  of  the  green  oil. 
