AmNJo°vU'i8P9?arm-}      Raphides  the  Cause  of  Acridity.  545 
cal  composition,  and  thus  the  difference  in  their  action  be  accounted 
for.    This  question  the  writer  volunteered  to  answer. 
Accordingly,  four  plants  containing  raphides  were  selected,  two 
of  which,  the  Colocasia  and  Indian  turnip,  were  highly  acrid,  and 
two,  the  Fuchsia  and  Tradescantia,  or  Wandering  Jew,  were  per- 
fectly bland  to  the  taste. 
A  portion  of  each  plant  was  crushed  in  a  mortar,  water  or  dilute 
alcohol  was  added,  the  mixture  was  stirred  thoroughly  and  thrown 
upon  a  fine  sieve.  By  repeated  washing  with  water  and  decanting 
a  sufficient  amount  of  the  crystals  was  obtained  for  examination. 
From  the  calla  the  crystals  were  readily  secured  by  this  means  in  a 
comparatively  pure  state.  In  the  case  of  the  Indian  turnip  the 
crystals  were  contaminated  with  starch,  while  the  crystals  from  the 
fuchsia  and  tradescantia  were  imbedded  in  an  insoluble  mucilage 
from  which  it  was  found  impossible  to  separate  them.  The  crystals 
were  all  found  to  be  calcium  oxalate. 
Having  determined  the  identity  in  chemical  composition  of  the 
crystals,  it  was  thought  that  there  might  be  a  difference  of  form  of 
the  crystals  in  the  various  plants,  from  the  fact  that  calcium  oxalate 
crystallizes  both  in  the  tetragonal  and  the  monoclinic  systems.  A 
laborious  microscopic  examination,  however,  showed  that  this 
theory  also  had  to  be  abandoned.  The  fuchsia  and  tradescantia 
contained  bundles  of  raphides  of  the  same  form  and  equally  as  fine 
as  those  of  the  acrid  plants.  At  this  point  in  the  investigation  the 
writer  was  inclined  to  the  opinion  that  the  acridity  of  the  Indian 
turnip  and  calla  was  due  to  the  presence  of  an  acrid  principle. 
Since  the  works  on  pharmacy  claimed  that  the  active  principle  of 
the  Indian  turnip  was  soluble  in  ether,  the  investigation  was  con- 
tinued in  this  direction.  A  large  stem  of  the  calla  was  cut  into 
slices,  and  the  juice  expressed  by  means  of  a  tincture  press.  The 
expressed  juice  was  limpid  and  filled  with  raphides.  A  portion  of 
the  juice  was  placed  into  a  cylinder  and  violently  shaken  with  an 
equal  volume  of  ether.  When  the  ether  had  separated  a  drop  was 
placed  upon  the  tongue.  As  soon  as  the  effects  of  the  ether  had 
passed  away,  the  same  painful  acridity  was  experienced  as  is  pro- 
duced when  the  plant  itself  is  tasted.  This  experiment  seemed  to 
corroborate  the  assumption  of  an  acrid  principle  soluble  in  ether. 
The  supernatant  ether,  however,  was  slightly  turbid  in  appearance, 
a  fact  which  was  at  first  ignored.    Wishing  to  learn  the  cause  of 
