394  Heloderma  Saspectiim,  Cope.         {  ^aS^sot™' 
The  poisonous  liquid  drawn  out  of  the  sponge  by  means  of  the 
weak  solution  of  salt  was  afterwards  subcutaneously  injected  into 
frogs,  white  mice  and  rabbits,  which  all  died  of  it.  By  special 
experiments,  I  convinced  myself  that  there  was  no  other  poison  in 
the  sponge,  syringe,  canula,  etc.  The  common  symptom  was  a 
paralyzation  of  the  nervous  system,  setting  in  gradually  after  a  short 
lapse  of  time  and  ultimately  causing  death.  Convulsions  were  not 
observed  in  rats,  and  in  rabbits  only  in  a  very  slight  degree  towards 
the  end  (suffocating  convulsions  slightly  indicated).  In  frogs  the 
poisoning  lasted  from  57  minutes  to  several  hours,  a  day  and  a 
night,  etc.;  in  rats  56  to  85  minutes  ;  a  little  rabbit  lived  1 12  minutes. 
The  frogs  died  of  paralyzation  of  the  heart  ;u  the  animals,  on  the 
contrary,  seemed  to  die  of  the  gradual  paralyzation  of  the  nervous 
system  and  the  centres  of  respiration.  If,  on  prolonged  irritation  of 
these  latter  systems,  the  heart  had  been  primarily  paralyzed,  signs 
of  acute  inner  suffocation,  accompanied  by  dyspnoea  and  violent  con- 
vulsions should  have  appeared,  as  was  the  case  in  the  experiments 
of  Weir  Mitchell  and  Reichert  (see  note  6) ;  but  such  was  not 
the  case  to  any  degree  worth  mentioning.  The  difference  between 
the  results  of  these  investigators  and  my  own  surely  depend  chiefly 
on  their  having,  as  a  rule,  used  much  greater  doses  than  I  did ;  they 
have,  therefore,  obtained  a  sudden  paralyzation  of  the  heart,  while 
my  experiments  have  brought  about  very  gradual  paralyzation  of 
the  nervous  system. 
On  account  of  the  way  in  which  I  collected  the  poison,  I  cannot 
say  how  great  the  doses  were.  The  quantity  of  saliva  taken 
amounted  on  one  occasion  to  about  0-3  gramme,  but  surely  both 
the  quantity  and  the  toxicity  varied  much  on  different  occasions. 
That  the  poison  is  effective  in  very  small  quantities  was  proved  by 
the  following  experiment:  1-8  milligrammes  of  dried  poison  was  dis- 
persed in  a  little  water,  only  partly  dissolved ;  was  filtered  and  in- 
jected into  a  frog.  The  animal  grew  very  weak  and  languid,  but 
was,  however,  not  totally  paralyzed  ;  did  not  completely  recover 
until  after  a  week.  The  poisonous  part  of  this  dose  was  certainly 
not  more  than  a  fraction  of  1  milligramme. 
A  more  minute  examination  of  the  development  of  the  paralysis 
11  Frogs  can,  as  a  rule,  hardly  die  from  paralyzation  of  the  respiratory  organs, 
since  they  breathe  so  sufficiently  through  their  skin  that  they  can  lie  alive  for 
weeks  without  lung  respiration  and  afterwards  recover. 
