Amslpt?i876rm'}  'Fucus  Vesiculosus.  397 
used  in  winter  for  feeding  horses,  cattle  and  sheep,  and  is  eaten  by  deer 
when  other  food  is  scarce. 
F.  nodosus,  Lin.,  knobbed  sea-wrack,  grows  in  similar  localities,  but 
at  or  near  low-water  mark.  It  attains  a  length  of  4  to  6  feet,  and  has 
a  narrower  veinless  frond,  with  the  branches  almost  filiform  at  the 
base,  the  vesicles  single  in  the  center  of  the  thallus,  or  frond,  ovate  in 
shape  and  usually  quite  large. 
F.  serratus,  Lin.,  has  a  veined  and  serrate  frond,  and  is  destitute  of 
vesicles. 
F.  siliquosus,  Lin.,  s.  Cystoseira  siliquosa,  Agardh,  has  a  very  narrow 
frond,  2  to  4  feet  long,  with  short  branches,  articulated  vesicles  and 
lanceolate  flattened  sporocarps. 
F.  natans,  Lin.,  s.  Sargassum  bacctferum,  Agardh,  the  gulf-weed  of 
the  Atlantic  Ocean,  is  often  found  in  immense  masses  floating  in  the 
sea.  Its  frond  is  terete,  with  the  branches  linear  and  serrate  and  the 
vesicles  globular  and  aculeate. 
All  these  and  many  allied  species  appear  to  be  very  similar  in  their 
constituents,  of  which  they  contain  mucilage,  mannit,  odorous  oil,  bit- 
ter principle  and  a  considerable  proportion  of  saline  matter,  varying 
from  14  to  20  per  cent.,  calculated  for  the  dry  plants.  According  to 
Godeschen,  James  and  others,  the  variation  is  just  as  great  for  the 
bladder  wrack  as  collected  in  different  localities,  and  it  is  not  impossi- 
ble that  this  may  be,  at  least  in  part,  accounted  for  by  having  been  col- 
lected in  different  seasons,  the  plant  being  assumed  to  be  most  active 
when  collected  after  the  sporocarps  have  formed,  about  the  month  of 
July.  E.  Marchand  found  (1865)  in  the  ashes  of  F.  vesiculosus  0719 
per  cent,  iodine  and  0*603  per  cent,  bromine  ;  in  F.  siliquosus  nearly 
the  same  amount,  and  in  F.  serratus  0*834  iodine  and  1*007  bromine, 
while  the  ashes  of  the  fucoideae  Laminaria  aigitata,  Lamx.  contained 
5*352  iodine  and  0*774  bromine,  and  Lam.  saccharina,  Lamx.  about 
one-half  these  amounts  (see  also  "Am.  Jour.  Phar.,"  1854,  P-  43^). 
Bladder  wrack  has  been  employed  in  France  in  the  form  of  extract, 
prepared,  according  to  Dannecy,  by  exhausting  the  plant  with  54  per 
cent,  alcohol  ;  it  is  stated  to  represent  15  parts  of  the  fucus  ("  Proc. 
Am.  Phar.  Assoc.,"  1863,  p.  66)  ;  also  in  the  form  of  syrup,  sug- 
gested by  Potier  (Ibid.),  by  exhausting  150  parts  of  the  powdered  plant 
with  14  per  cent,  alcohol,  evaporating  the  tincture  to  230  parts  and 
dissolving  in  it  370  parts  of  sugar  ;  20  grams  (1  tablespoonful)  of  this 
