ON  THE  MILKY  JUICE  OF  LACTUCA  ELONGATA,  MUHL.  145 
ON  THE  MILKY  JUICE  OF  LAOTUCA  ELONGATA,  MUHL- 
ENBERG. 
By  John  M.  Maisch. 
Lactusa  elongata,  Muhl.,  is  now  generally  described  as  a 
variety  of  L.  Canadensis,  Lin.,  under  wliicb  name  all  the  different 
forms  of  Lactuca  are  comprised  which  are  indigenous  to  Canada 
and  the  Northern  and  Middle  States  of  the  Union  ;  but  this  species 
is  likewise  met  with,  though  less  frequently,  in  the  Southern 
States.  It  is  a  coarse  plant,  growing  in  hedges  and  thickets,  in 
somewhat  damp  situations,  and  in  favorable  places  its  annual 
stem  often  exceeds  eight  feet  in  height.  The  inflorescence  usually 
forms  long  and,  at  first,  rather  dense  panicles,  but  it  is  iilso  met 
with  in  rather  loose,  compound  racemes.  The  foliage  is  ex- 
tremely variable,  and  in  the  same  situation  specimens  may  fre- 
quently be  seen  with  the  leaves  varying  from  runcinate  pinna- 
tifid  to  entire,  and  with  the  base  rounded  to  sagittate  and  even 
amplexicaul.  Its  flowers  begin  to  appear  in  July  and  the  fruit 
to  ripen  in  the  month  of  August ;  but  flowers  and  fruits  may 
usually  be  found  in  the  same  plant  till  late  in  September  and 
even  in  October. 
Like  other  species  of  the  same  genus,  this  plant  is  lactescent 
in  all  its  parts  above  ground,  and  the  greatest  number  of  th^ 
vessels  carrying  the  milky  juice  are  found  immediately  beneath 
the  thin  bark,  so  that  a  very  slight  incision  will  at  once  produce 
a  milk-white  exudation.  Our  species  therefore  resembles  in  these 
respects  the  two  species  from  which,  in  Europe,  lactucarium  is 
produced,  namely,  Lactuca  virosa  and  sativa,  Lin.,  and  it  "^vas 
reasonable  to  suppose  that  they  all  might,  to  a  certain  extent, 
resemble  each  other  in  their  medical  properties.  In  regard  to 
this  point  we  find  the  following  passage  in  the  U.  S.  Dispensa- 
tory, 12th  ed.,  page  503  : 
"  It  was  supposed  that  our  native  L.  elongata^  or  ivild.  lettuce^ 
might  have  similar  virtues ;  and  Dr.  Bigelow  was  informed  by 
physicians  who  had  employed  it,  that  it  acts  as  an  anodyne,  and 
promotes  the  secretion  from  the  skin  and  the  kidneys.  But 
according  to  M.  Aubergier,  who  experimented  with  different 
species  of  Lactuca,  in  order  to  ascertain  from  which  of  them  lac- 
10 
