MEDICINAL  VALUE  OF  THE  CANTHARIS  VITTATA,  ETC  195 
allowed  to  remain  in  a  covered  vessel  for  twenty-four  hours ; 
then  transferred  to  a  small  displacing  apparatus  and  two  ounces 
of  sulphuric  ether  allowed  to  percolate.  The  ethereal  solution 
was  colorless,  and  on  evaporation  the  residue  consisted  of  nearly 
pure  cantharidin,  having  a  slight  tinge  of  yellow  which  was  re- 
moved by  treating  it  with  alcohol  and  carefully  drying.  The 
amount  of  cantharidin  thus  obtained  from 
A.  500  gr.  of  the  Cantharis    vesicatoria  was      gr.  2,03 
B.  The  amount  of  cantharidin  obtained  from 
the  Cantharis  vittata  in  a  similar  manner, 
was  found  to  be  gr.  1.99 
O.  The  Mylabris  cichorii  treated  likewise  yielded     gr.  2.18 
From  a  want  of  time  and  opportunity  no  regard  could  be  paid 
to  the  rest  of  the  constituents  of  the  two  last  specimens  operated 
upon,  and  I  much  regret  that  consequently  I  cannot  carry  the 
more  important  of  my  investigations  to  the  extent  I  desire. 
Preparatory  to  the  above  results,  I  prepared  a  small  quantity  of 
cerate  from  the  several  specimens,  according  to  our  U.  S.  P, 
I  prepared  then  a  small  blister  of  each  cerate  and  applied  them 
to  my  arm,  watching  closely  the  result, 
I  observed  that  the  cerate  prepared  from  the  Mylabris  was 
first  to  cause  rubefacience,  and  in  a  shorter  space  of  time  pro- 
duced the  most  perfect  blister. 
There  was  hardly  a  perceptible  difference  between  that  pro- 
duced by  the  C.  ves.  and  C.  vit.;  they  were  not  so  full,  nor  were 
they  so  speedily  produced  as  that  by  the  Mylabris. 
The  above  facts,  the  result  of  careful  experiment,  show  con- 
clusively that  the  Cantharis  vittata  is  but  in  an  inappreciable 
degree  inferior  to  the  C.  vesicatoria. 
The  difference  in  amount  of  cantharidin  which  they  contain 
scarcely  exceeds  two  per  ct.,  and  this  investigation  will  greatly 
tend  to  corroborate  the  numerous  statements  that  have  been 
made  relative  to  the  value  of  the  C,  vittata  as  a  vesicant. 
That  C.  vesicatoria,  was  first  introduced  and  having  been 
long  used  almost  universally,  and  found  to  answer  every  pur- 
pose, is  not  therefore  necessary  evidence  of  its  superior  efficacy, 
nor  is  it  any  argument  that  it  should  be  used  in  preference  to 
our  Cantharis,  capable  of  accomplishing  the  same  service  and 
preferable  in  many  respects. 
