350 
'  Active  Pf'inciple  in  Vesicating  Insects. 
j  Am.  Jour.  Pharm. 
1       July,  1885. 
THE  SEAT  OF  THE  ACTIVE  PRINCIPLE  IN  VESICAT- 
ING INSECTS.^ 
By  H.  Beauregard. 
The  author  has  made  an  attempt  to  solve  the  hitherto  incompletely 
elucidated  question  as  to  the  exact  seat  of  the  cantharidin  in  the  bodies 
of  vesicating  insects,  using  in  liis  investigations  the  ordinary  European 
Cantharis  vesicatoria,  of  which  he  was  favored  with  a  good  supply. 
The  result  of  the  researches  upon  this  point  made  by  Berthoud,  Ferrer, 
Fumouze  and  Lissonde,  using  chemical  methods,  may  be  summed  up 
in  the  })roposition  tliat  "the  soft  parts  are  much  more  active  than  the 
hard  parts  (elytra,  legs  and  head)/'  Courbon,  experimenting  physio- 
logically upon  Epicauta  adspersa,  denied  that  the  hard  ])arts  exercised 
any  epipastic  action,  and  Leidy,  speaking  of  Epicauta  vittata,  went 
further,  and  said  of  this  species  that  "the  vesicating  principle  resides 
in  the  blood  and  in  a  fatty  matter  peculiar  to  certain  glands  accessory 
to  the  generative  organs  and  in  the  eggs"  (see  "  Am.  Jour.  Phar.,  1860, 
p.  157. 
The  author  in  liis  experiments  estimated  the  vesicating  property  of 
the  substance  under  examination,  by  applying  to  his  arm  either  a  mois- 
tened powder  of  the  particular  parts  of  the  insect,  or  the  mixture  of 
oil  and  crystals  obtained  by  macerating  them  twelve  hours  in  acetic 
ether,  expressing,  filtering  and  evaporating.  In  this  way  he  ascertained 
that  in  the  case  of  Cantharis  vesicatoria  the  blood  is  vesicant  in  a  rather 
high  degree,  whilst  the  hard  parts,  free  from  blood,  are  absolutely 
inactive.  As  to  the  soft  parts^  he  found  that  the  muscles,  respiratory 
and  digestive  organs,  fat,  and  malpighian  tubes  are  quite  devoid  of 
epispastic  power,  which  resides  solely  in  the  genital  apparatus. 
In  the  male  the  testicles  and  the  deferent  canals  are  inactive,  but  an 
energetic  vesicant  property  was  found  to  reside  especially  in  the  pair  of 
seminal  vesicules  situated  in  much  elongated  cylindrical  tubes.  The 
applicatation  to  the  forearm  of  a  small  portion  of  one  of  these  vesicules 
determined  the  formation  of  a  voluminous  blister,  with  a  painful  tume- 
faction at  the  periphery.  Sometimes  a  blister  was  obtained  with  the 
part  of  the  deferent  canals  nearest  to  these  tubes,  but  this  was  attributed 
to  sperm  contained  in  the  canals,  for  in  the  majority  of  cases  these  were 
found  to  be  completely  inactive. 
1  From  a  paper  read  before  the  French  Association  for  the  Advancement 
of  Science.    ("  Bulletin  Commercial,"  xii,  437.) 
