Am"/a°nu!'i£9arm'}         R°ot  °f  Vernonia  Nigritiana.  41 
eventually  the  influence  of  the  drug  passed  off.  A  larger  dose  (&ths 
grain)  reduced  the  number  of  beats  by  one-third,  the  ventricles  evi- 
dently filling  slowly.  A  still  larger  dose  (roths  grain)  almost  ar- 
rested the  heart  in  systole,  diastole  only  taking  place  imperfectly  and 
at  long  intervals ;  eventually  the  heart  stopped  completely  in  systole. 
A  pigeon  was  not  influenced  by  f ths  of  a  grain,  but  2J  grains  killed 
it,  the  heart  being  arrested  in  systole. 
The  action  of  vernonin  on  the  heart  thus  resembles  that  of  digitalis. 
Heckel  and  Schlagdenhauffen,  however,  consider  that  it  is  twenty- 
four  times  weaker  than  the  soluble  principle  of  digitalis  (digitalein). 
They  have  studied  the  action  of  the  drug  on  the  skeletal  nerves  and 
muscles,  and  have  come  to  the  conclusion  that  it  paralyzes  locally 
nerves  to  which  it  is  applied,  but  does  not  markedly  influence  the 
muscles.  If  the  drug  be  injected  under  the  skin  of  the  thigh  it  soon 
comes  to  pass  that  galvanizing  the  sciatic  on  this  side  ceases  to  con- 
tract the  muscles  supplied  by  it,  whilst  muscles  respond  equally  to  the 
current  on  the  two  sides  when  directly  stimulated. 
Further  experiments  are  adduced  to  show  that  the  drug  directly 
destroys  the  conducting  power  of  the  sciatic  nerve  in  the  frog,  and 
that  in  warm-blooded  animals  it  paralyzes  the  limb  into  which  it  is 
injected.  The  experimenters,  however,  have  by  no  means  fully  shown 
the  influence  of  vernonin  on  the  nerve  and  muscle  tissues,  and  some 
serious  sources  of  fallacy  seem  to  have  been  overlooked.  It  may  be 
presumed  that  a  drug  which  so  powerfully  influences  the  nerves  must 
also  affect  the  nerve  endings, but  no  experiments  on  this  point  seem  to 
have  been  made.  No  means  seem  to  have  been  employed  to  prevent 
the  circulation  of  poisoned  blood  from  the  injected  to  the  non-injected 
leg ;  indeed,  the  investigations  would  lead  to  the  conclusion  that  the 
drug  is  not  thus  carried,  for  it  is  stated  that  when  the  poison  is  in- 
jected under  the  skin  of  the  back,  stimulation  of  the  sciatic  nerves 
continues  to  cause  contraction  of  the  muscles.  From  this  it  would 
follow  that  either  the  poison  does  not  reach  the  nerve  endings  of  the 
leg  muscles  when  injected  under  the  skin  of  the  back,  or  that  it  does 
not  paralyze  them.  Further  investigations  must  be  made  before  the 
conclusions  of  Messrs.  Heckel  and  Schlagdenhauffen  can  be  accepted, 
but  they  have  introduced  us  to  a  substance  which  manifestly  has  most 
interesting  pharmacological  properties  and  may  have  important  thera- 
peutic uses. 
D.  J.  Leech. 
