374 
Polygonum  Hydropiper. 
f  Am.  Jour.  Pharm. 
\       Aug.,  1886. 
calling  attention  to  several  statements,  to  which  I  shall  respond  with 
the  greatest  of  pleasure. 
Ad  1  and  2. — Tf  I  did  not  question  that  part  of  their  paper  referred 
to  the  reason  was  that  I  overlooked  it.  But  let  me  state  here,  that 
if  my  process  or  processes  are  minutely  followed,  no  tannic  acid  can  be 
separated  in  sufficient  quantity  to  produce  a  precipitate  with  gelatin. 
(I  do  not  mean  to  state  tint  smart-weed  contains  no  tannic  acid.) 
If  my  article  of  1871  is  carefully  read,  it  will  be  seen  that  this  acid, 
after  being  separated  from  the  organic  matter  and  sulphide  of  lead 
by  means  of  ether  (when  I  speak  of  ether  I  mean  absolute  ether),  and 
then  simply  allowed  to  evaporate  without  purification,  of  necessity 
must  contain  some  impurity,  but  that  impurity  is  not  tannin.  The 
only  difference  between  the  process  of  1871  and  the  process  of  1886, 
is  purification  of  the  acid.  Any  other  differences  in  the  processes  de- 
pend upon  definite  chemical  action,  namely,  the  substituting  of  sul- 
phuretted hydrogen  for  sulphuric  acid  in  one  case,  and  the  substitut- 
ing of  bicarbonate  of  sodium  for  subacetate  of  lead  in  the  other. 
If  the  gentlemen  will  examine  minutely  that  portion  of  their  ether 
extract  that  was  soluble  in  water,  which  they  have  entirely  over- 
looked or  forgotten  (see  Am.  Jour.  Phar.,  1885,  p.  21),  they  will 
find  something  of  great  interest  to  them. 
Ad  3. — Messrs.  Trimble  and  Schuchard  state  that  "  it  is  very  poor 
chemistry  to  judge  of  the  unknown  constituents  of  a  plant  by  its 
physiological  action,  or  by  the  appearance  of  an  ether  residue  under 
the  microscope."  Indeed,  this  is  actonishing  !  What  about  the  physi- 
ological action  of  strychnia,  morphia,  atropia  and  a  host  of  others  ? 
Is  not  the  action  of  these  alkaloids  such  that  you  can  be  positive  of 
their  presence  without  any  other  chemical  evidence  ?  Let  us  suppose 
a  hypothetical  case  of  poisoning.  I  he  man  swallowed  something,  we 
don't  know  what,  but  we  find  him  in  the  following  condition  :  A  scar- 
let rash  all  over  the  body,  great  dilatation  of  the  pupils,  dryness  of 
the  fauces,  constriction  about  the  chest,  difficulty  of  deglutition,  etc. 
Any  intelligent  scientist  would  know  that  this  man  had  either  taken 
atropia,  daturia  or  hyoscyamia;  daturia  could  be  excluded,  because 
atropia  and  daturia  are  chemically  and  physiologically  identical,  and 
hyoscyamia  can  also  be  excluded,  upon  the  ground  that  this  alkaloid 
produces  no  scarlet  rash  upon  the  body.  But  to  verify  it,  there  is 
none  of  the  substance  left,  for  the  man  had  swallowed  all.  A  post 
mortem  is  made,  the  contents  of  the  bladder  and  stomach,  as  well  as 
