AND  PHYSIOLOGICAL  ACTION  IN  MEDICINES. 
441 
the  promotion  of  a  definite  change  in  the  constitution,  and  to 
examine  the  modification  which  the  physiological  action  has 
undergone.  Such  has  been  the  plan  which  the  authors  have 
pursued ;  the  bodies  which  they  have  chosen  for  examination 
are  the  more  active  of  the  vegetable  alkaloids,  and  the  chemical 
operation,  of  which  they  have  studied  the  effect,  has  been  the 
direct  addition  of  iodide  of  methyl.  It  was  shown  by  How 
that,  when  iodide  of  methyl  acts  upon  strychnia,  brucia,  morphia 
and  other  alkaloids,  it  adds  itself  to  them,  and  beautiful  crys- 
talline bodies  are  produced  which  differ  considerably  in  charac- 
ter from  the  salts  of  the  alkaloids.  The  authors  have  already 
examined  the  physiological  action  of  the  bodies  produced  by  the 
addition  of  iodide  of  methyl  to  strychnia,  brucia,  morphia, 
thebaia,  codeia,  and  nicotia. 
The  iodide  of  methyl-strychnium  is  prepared  by  first  treating 
finely  pulverized  strychnia  with  a  solution  of  carbonate  of  potash 
in  dilute  alcohol,  and  then  adding  an  excess  of  iodide  of  methyl 
mixed  with  about  its  own  volume  of  rectified  spirit,  and  digest- 
ing in  a  flask  for  twenty-four  hours.  The  spirit  is  thereafter 
distilled  off,  the  residue  dissolved  in  water,  and  crystallized.  It 
is  well  known  that  doses  of  strychnia,  varying  from  one-twentieth 
to  one-thirtieth  of  a  grain,  rapidly  produced  in  rabbits  most 
violent  convulsions,  and  in  a  few  minutes  kill  the  animal ;  the 
phenomena  produced  being  due  to  a  localization  of  its  action  on 
the  cord.  It  was  found  that  twelve  grains  of  iodide  of  methyl- 
strychnium,  when  administered  (by  subcutaneous  injection)  to 
rabbits  weighing  three  pounds,  produced  no  effect  whatever. 
Fifteen  grains  produced  symptoms,  and  twenty  killed  ;  but  the 
animal  died  with  symptoms  altogether  different  from  those  pro- 
duced by  strychnia.  In  place  of  violent  and  spasmodic  convul- 
sions and  muscular  rigidity,  the  appearances  were  those  of  para- 
lysis with  complete  general  flaccidity.  The  spinal  motor  nerves 
were  either  paralyzed,  or  speedily  become  so ;  and,  instead  of 
the  speedy  occurrence  of  muscular  rigidity,  the  muscles  remained 
flaccid,  contractile,  and  alkaline  for  several  hours.  In  short, 
by  the  addition  of  iodide  of  methyl  to  strychnia,  the  toxic  prop- 
erties of  the  latter  are  diminished  about  140  times ;  and  the 
body  produced  possesses  the  physiological  action  of  curare,  viz., 
paralysis  of  the  end-organs  of  the  motor  nerves. 
