120         WEEDS  OF  WESTERN  PEPPERMINT  PLANTATIONS. 
and  popular,  as  then  the  whole  of  the  active  matter  could  be 
fully  extracted  without  difficulty. 
There  still  arises  the  question,  whether  glycerin  is  capable  of 
arresting  fermentation  in  all  preparations  wherein  it  takes  the 
place  of  sugar.  It  is  well  known  that  it  possesses  great  pre- 
servative powers,  but  whether  it  would  meet  every  emergency, 
time  alone  can  determine.  The  writer  does  not  think  it  neces- 
sary to  further  enlarge  upon  the  matter,  but  leaves  it  to  the 
careful  consideration  of  all  who  feel  interested  sufficiently  to 
fully  investigate  the  subject. 
PJdladelphia,  Feb.,  1870. 
THE  WEEDS  OF  WESTERN  PBPPEBMINT  PLANTATIONS. 
By  John  M.  Maisch. 
On  pages  449  to  459  of  the  Proceedings  of  the  American 
Pharmaceutical  Association  for  the  year  1858,  there  is  printed  a 
very  valuable  paper  by  Frederick  Stearns,  which  is  entitled 
"  The  Peppermint  Plantations  of  Michigan,"  was  copied  at  that 
time  into  many  American  and  European  periodicals,  and  is  now 
frequently  referred  to  in  standard  works  on  materia  medica.  It 
is  stated  in  this  paper  that  the  weed  which  appears  in  the  mint 
plantations  is  ErecJitliites  hieraeifolia^  known  by  the  common 
names  of  horse-tail,  cow's-tail,  mare's-tail,  field-broom,  bitter- 
weed  and  fireweed.  Mr.  Stearns  states,  after  Asa  Gray,  that 
Erechtliites  grows  in  moist  woods  and  recent  clearings,  but  does 
not  explain  the  contradicting  fact  that  the  same  plant  should  ap- 
pear in  peppermint  plantations  during  the  second  year,  and  in- 
crease from  year  to  year.  The  habit  of  Erechthites^  as  I  have 
noticed  it  near  Philadelphia,  is  correctly  stated  in  botanical 
works  ;  it  appears  in  new"  clearings,  particularly  where  the  ground 
has  been  burned  over,  but  it  disappears  from  cultivated  open 
fields.  Notwithstanding  this  irreconcilableness,  there  was  no 
apparent  reason  for  doubting  the  correctness  of  Mr.  Stearns' 
statement,  since  the  plant  is  very  easily  recognized  and  the  facts 
are  stated  with  positiveness. 
In  October  last  Messrs.  Powers  &  Weightman  referred  to  me 
a  letter  from  Mr.  C.  A.  Ensign,  of  Centreville,  Mich.,  together 
