Am/f^i89i"m'}    Action  of  Morphine  and  Derivatives.  27 
lethal  dose  of  these  compounds  was  found  to  be  smaller,  owing  to 
their  increased  tendency  to  cause  convulsions.  The  action  of  all 
three  substances  was  practically  identical ;  they  all  affect  the  same 
parts  of  the  central  nervous  system  as  morphine,  though  they  do 
not  influence  these  parts  in  the  same  degree.  It  would  seem  that 
if  the  same  atom  of  hydrogen  be  replaced,  it  does  not  matter  which 
alkyl  radicle  is  substituted,  though  it  is  possible  that  further  investi- 
gations may  indicate  some  quantitative  difference  so  far  as  regards 
their  action  on  the  different  parts  of  the  nervous  system. 
Substitution  of  acid  radicles. — Four  compounds  were  prepared  in 
which  one  or  two  equivalents  of  hydrogen  were  replaced  by  acetyl 
or  benzoyl,  viz : 
Acetylmorphine,   C1  7HX  8(C2H30)N03 
Diacetylmorphine,   C17H17(C2HgCM2N03 
Benzoylmorphine,   Ca  ^  8(C7H50)N03 
Dibenzoylmorphine,   C17H17(C7H50)2N03 
The  substances  thus  produced  have  almost  identical  physiological 
effects.  It  seemed  quite  indifferent  which  acid  radicle  was  intro- 
duced, and  whether  one  or  both  hydrogen  atoms  were  replaced. 
The  tetanizing  power  of  all  four  was  much  greater  than  that  of 
morphine,  their-  narcotic  action  distinctly  less.  The  depressant 
action  of  small  doses  on  the  cord  and  on  the  respiratory  centre  is 
very  much  greater  than  that  of  morphine.  Compared  with  codeine 
they  produce  an  equal  narcotic  effect  with  about  one-tenth  the  doser 
whilst  about  three  times  larger  dose  is  necessary  to  cause  tetanus ; 
their  depressant  action  on  motor  nerves  is  about  the  same.  Acetyl- 
morphine affects  the  heart  more  than  codeine. 
Substitution  of  chlorine. — Compounds  were  produced  by  substitut- 
ing chlorine  for  the  atoms  of  hydrogen  in  morphine  and  codeine. 
In  trichloromorphide  C17H16Cl3NO  both  the  hydroxyl  groups  and 
one  hydrogen  atom  have  been  replaced  by  three  atoms  of  chlorine. 
The  new  alkaloid  acts  primarily  on  the  central  nervous  system,  and 
causes  depression,  followed  by  tetanus.  It  has  a  marked  paralyzing 
action  on  the  motor  nerves,  and  has  some  slight  action  as  a  muscle 
poison. 
In  chlorocodide  C18H2C1N02  a  hydroxyl  group  in  codeine  has  been 
replaced  by  chlorine.  Chlorocodide  causes  narcotic  and  tetanic 
symptoms  in  frogs  to  much  the  same  degree  as  codeine.    Its  action 
