Am.  Jour.  Pharm.  ) 
July,  1875.  ; 
Commercial  Sponges. 
may  ever  after  give  him  a  new  motive  and  zest  in  his  work.  The 
most  of  us  will  use  sponges  in  an  indefinite  variety  of  ways,  all  our 
lives,  without  even  once  stopping  to  think  how  they  were  formed  ; 
whether  they  are  plants,  animals,  or  neither,  or  what  are  their  history 
and  habits. 
The  ordinary  sponges  of  commerce,  which  we  use  so  extensively, 
have  but  little  resemblance  to  animals  or  plants,  and  belong  to  a  class  of 
organic  bodies  concerning  the  affinities  and  classifications  proper  of  which 
there  has  been  much  doubt.  And  this  doubt  has  led  naturalists  to  apply 
the  question-begging  appellation  of  zoophytes,  or  plant  animals,  to 
these  and  similar  organisms.  They  are  now  generally  considered  mem- 
bers of  the  animal  kingdom.  The  parts  we  use  are  the  mere  skeletons, 
composed  of  a  kind  of  horny  substance.  The  animal  itself  is  a  soft, 
jelly-like,  amorphous  mass,  which  fills  up  all  the  intercellular  spaces, 
lines  the  tubular  canals,  and  forms  a  jet  black  or  sometimes  a  dark  pur- 
plish skin  on  the  outside,  covering  the  whole  skeleton,  excepting  the 
larger  openings,  which  project  beyond  its  general  surface.  In  this  form 
the  sponge  exists  in  the  water,  and,  out  of  its  native  element,  is  hard 
and  glistening  on  the  outside,  and  verv  strongly  resembles  a  piece  of 
liver. 
The  mode  of  life  in  this  low  order  of  existence,  which  is  regarded 
as  a  compound  animal,  is  very  simple,  and  we  would  be  disposed  to  call 
it  extremely  uneventful.  Sponges  grow,  by  a  kind  of  lichen-like  root, 
to  some  foreign  object  on  the  sea  floor,  and  never  move  from  their 
position  ;  they  have  no  power  to  contract  or  expand  their  bodies  as  a 
whole,  or  any  part  of  it ;  and  they  are  quite  insensible  to  every  sort  of 
irritation.  I  heir  only  power  seems  to  be  that  of  absorbing  large  quan- 
tities of  water,  which  they  again  yield  up  on  pressure  without  any  in- 
jury to  their  texture.  The  water,  which  permeates  their  whole  mass, 
and  maintains  a  constant  circulation  through  it,  keeps  the  skeleton  soft 
and  elastic,  brings  to  the  animals  the  air  and  food  on  which  they  sub- 
sist, and  carries  away  waste  matter  from  the  body. 
On  examination  of  a  sponge  skeleton,  it  will  be  seen  that  the  porous 
surface  is  finer  and  of  closer  texture  than  the  interior,  that  there  are 
large  apertures  scattered  indiscriminately  over  the  surface,  and  between 
these  are  much  finer  openings,  covering  the  complete  outer  surface  of 
the  sponge.  The  latter  are  called  pores,  and  serve  as  channels  of  en- 
trance to  the  water,  which,  after  circulating  through  the  body  by  means 
of  the  tortuous  and  branching  canals  which  makeup  its  inner  skeleton, 
