FORMATION  OF  ELLAGIC  ACID  BY  MEANS  OF  GALLIC  ACID.  141 
difficulty  in  moving  my  lower  limbs.  It  is,  however,  possible 
that  the  disturbance  of  the  sensory  functions  may  set  in  simul- 
taneously with  those  of  the  motory,  for  the  loss  of  taste  of  the 
emetic  solution  which  I  drank  I  experienced  but  a  few  minutes 
after  I  had  swallowed  the  poison.  The  violent  form  of  asthma 
which  preceded  recovery  in  my  case,  and  which  has  been 
uniformly  observed  in  similar  cases,  is  another  symptom  which 
lends  weighty  support  to  the  opinion  that  the  motor  element  of 
the  respiratory  function  is  originally  affected  by  the  poisonous 
action  of  prussic  acid  and  its  compounds — and  if  this  be  true,  it 
may  suggest  a  solution  of  the  much-vexed  question  of  the  patho- 
logy of  asthma.  The  temporary  paralysis  of  the  motor  nerves, 
whether  at  their  centric  origin  in  the  medulla  oblongata,  or  along 
their  distribution  to  the  respiratory  apparatus,  from  any  cause 
whatever,  would  be  sufficient  to  give  rise  to  all  the  symptoms 
characteristic  of  true  asthma.  There  can  hardly  be  a  doubt 
that  the  feeling  of  constriction  about  the  chest,  or  the  gasping 
for  air,  which  has  been  witnessed  in  cases  like  my  own,  is  but  an 
abatement  of  the  paralytic  effects  of  the  poison  on  the  nerve- 
centres,  which  supply  the  respiratory,  and  perhaps  also  the  cir- 
culatory system,  with  adequate  innervation. 
[It  may  not  be  out  of  place  to  here  call  attention  to  the  im- 
portant observations  of  M.  W.  Preyer,  noticed  in  our  preceding 
number,  p.  577,  who  asserts  that  the  subcutaneous  injection  of 
sulphate  of  atropia,  if  made  pretty  quickly  after  the  ingestion 
of  prussic  acid,  is  an  unfailing  antidote^  provided  a  sufficient 
dose  of  the  acid  has  not  been  taken  to  paralyze  the  heart. — Ed.] 
— Amer.  Journ.  Med.  Sci.,  Jan.,  1869. 
FORMATION  OF  ELLAGIO  ACID  BY  MEANS  OF  GALLIC 
ACID. 
By  M.  J.  Lowe. 
By  heating  nearly  to  the  boiling  point  for  several  hours  in  an 
aqueous  solution  of  two  equivalents  of  gallic  acid  and  one  of 
arsenic  acid,  a  crystalline  precipitate  is  deposited,  which  is  none 
other  than  ellagic  acid ;  the  best  way  is  to  mix  the  two  acids  in 
the  proportion  indicated  above,  add  water,  evaporate  to  dryness, 
heat  in  an  air  bath  to  120°,  and  extract  with  alcohol  at  90°, 
which  does  not  dissolve  ellagic  acid.  The  reaction  is  the  follow- 
ing— 
