412 
Action  of  Leeches  on  Blood. 
Am.  Jour.  Pliarm. 
Aug.,  1891. 
any  large,  coarse  weeds  which  may  spring  up  from  seeds  or  roots 
left  in  the  ground.  If  winds  blow  away  the  leaves  needed  as  a 
mulch,  a  few  old  dead  branches  of  trees  may  be  scattered  about  to 
hold  the  mulch  in  place.  At  the  end  of  the  third  season  the  roots 
will  have  reached  a  remarkable  size,  and  may  then  be  dug,  and  the 
same  bed  worked  over  and  restocked  with  seeds  or  small  plants. 
Some  who  have  tried  it  say  that  raising  ginseng  can  be  made 
profitable  where  a  man  has  suitable  land  in  the  forest  or  a  grove 
near  at  hand.  The  cost  of  preparing  a  bed  cannot  be  very  much, 
and  the  seed  can  be  obtained  from  the  wild  plants  in  our  forests. 
ACTION  OF  LEECH  EXTRACT  ON  BLOOD.1 
By  W.  L.  Dickinson. 
The  general  properties  of  the  extract  of  the  anterior  part  of  the 
dicinal  leech  which,  as  Haycraft  showed  (see  Am.  Jour.  Pharm.,  1886, 
p.  272),  possesses  a  strong  anti-clotting  action  on  blood,  are  the  follow- 
ing :  It  is  neutral  to  litmus  paper  ;  its  specific  gravity  is  not  appreciably 
higher  than  that  of  the  medium  used  for  extraction.  Boiling  causes 
no  precipitate,  and  no  loss  of  activity.  Alkalies  cause  no  precipitate. 
A  trace  of  acetic  acid  causes  cloudiness  readily  soluble  in  excess. 
Strong  acetic  acid  causes  no  precipitate  in  salt  free,  but  a  copious 
cloud  in  salt-saturated  extracts.  Nitric  acid  in  the  cold  causes  a 
precipitate  soluble  on  boiling,  and  reappearing  on  cooling.  Satura- 
tion with  ammonium  sulphate  causes  a  precipitate,  after  which  no 
proteid  remains  in  solution  ;  saturation  with  magnesium  sulphate  or 
sodium  chloride,  on  the  other  hand,  causes  no  precipitate.  If  all 
salts  are  removed  from  the  extract  by  dialysis,  there  is  no  precipi- 
tate produced,  and  no  loss  of  power.  Copper  sulphate,  lead  acetate, 
and  mercuric  chloride  give  precipitates  insoluble  in  excess  of  the 
reagents.  Copper  sulphate  and  potash  give  a  pink  (biuret)  reaction. 
Alcohol  causes  no  loss  of  the  activity  of  the  extract. 
The  leech  extract,  therefore,  contains  a  proteid  having  some 
features  in  common  with  Kiihne's  proto-,  and  others  with  deutero- 
albumose.  The  albumose  precipitated  by  ammonium  sulphate  has 
all  the  anti-clotting  power  of  the  original  extract ;  the  extract  minus 
the  albumose  has  no  such  powers.  Hence,  probably  the  albumose 
is  itself  the  active  principle. 
1  J.  Physiol.,  11,  566-572,  Jour.  Chem.  Soc,  1891,  482. 
