502  Hydration  of  Extracts.  {^^'Jm™' 
tion  and  can  be  obtained  in  the  shape  of  a  clear  slightly-colored 
liquid  by  simple  filtration.  If  this  clear  liquid  be  acidulated  by 
hydrochloric  acid,  the  quinovic  acid  is  precipitated  in  the  shape  of  a 
voluminous  jelly.  As  the  amount  of  quinovic  acid  is  generally  very 
small,  its  quantity  can  rarely  be  ascertained  with  accuracy,  unless 
the  amount  of  bark  be  not  under  40  grammes.  As  I  generally  make 
two  analyses  of  20  grammes  of  bark,  I  combine  the  mixture  of  qui- 
novic acid,  etc.,  of  the  two  filters  for  the  determination  of  the  quino- 
vic acid.  If  the  two  analyses  are  carefully  performed  under  the  same 
circumstances,  the  results  differ  only  very  slightly,  as  may  be  seen 
in  my  analysis  of  some  Jamaica  barks,  published  on  p.  121  of  this 
Journal. 
The  Hague,  11th  September,  1873. 
— Pharm.  Journ.  and  Trans. ,  Sept.  27,  1873. 
NOTE  ON  THE  HYDRATION  OF  EXTRACTS* 
By  Charles  Ekin,  F.CS. 
It  has  occurred  to  me  that  Wanklyn's  method  of  limited  oxidation 
by  means  of  an  alkaline  solution  of  potassium  permanganate  might 
be  applied  with  good  results  to  the  assay  of  such  medicinal  extracts 
as  are  dependent  for  their  activity  entirely,  or  for  the  most  part,  on 
certain  alkaloids —all  alkaloids  yielding  a  certain  portion  of  their 
nitrogen  as  ammonia.  Also  that  it  might  be  made  available  for  the 
determination  of  the  relative  values  of  the  first  year's  and  second 
year's  plant  of  hyoscyamus,  about  which  a  good  deal  has  been  taken 
for  granted  but  nothing  yet  really  proved.  And  again  in  the  case  of 
conium,  to  determine  which  has  the  greater  activity,  a  tincture  made 
from  the  fruit  or  from  the  leaves.  Of  course  the  difficulty  lies  in  the 
complete  and  easy  separation  of  the  vegetable  proteides  of  the  plant 
juices,  but  I  am  by  no  means  sure  that  this  is  not  a  difficulty  that  can 
be  overcome,  although  I  regret  I  have  not  yet  had  time  to  go  suffi- 
ciently into  the  subject  so  as  to  be  able  to  lay  results  of  any  value 
before  this  meeting  of  the  Conference.  I  have  had,  however,  inci- 
dentally to  determine  the  amount  of  water  in  various  extracts,  and 
have  thus  so  far  answered  question  66  on  the  blue  paper  circulated 
by  the  Conference,  viz.,  "  Is  it  possible  to  assign  a  definite  degree 
of  hydration  to  medicinal  extracts  with  a  view  to  uniformity  of 
strength  ?" 
*  Read  before  the  British  Pharmac.  Conference. 
