Am,reb.yiS9arm"}     Structure  of  Grindelia  Eobusta.  83 
found  a  layer  of  parallel  palisade  cells  containing  chlorophyll ;  the 
central  part  of  the  mesophyll  consists  of  spongy  parenchyma,  in  which 
the  vascular  bundles  are  imbedded.  These  bundles  are  closed,  colla- 
teral, and  are  surrounded  by  a  sheath  of  thick-walled  collenchyma, 
gradually  passing  into  the  hypoderma  of  the  upper  and  lower  surface 
of  the  leaf.  Rather  large  resin  ducts  are  put  within  this  collenchyma 
layer. 
Ths  involucre  of  the  flower  head  consists  of  spirally  arranged 
scales.  A  transverse  section  through  the  top  portion  of  these  scales 
is  nearly  circular,  and  is  covered  with  an  epidermis,  bearing  glands 
and  stomata  upon  the  outer  surface,  and  covering  several  tiers  of  pali- 
sade cells,  both  on  the  outer  and  inner  surface.  A  vascular  bundle 
in  the  centre  of  the  scale  is  surrounded  by  a  layer  of  collenchyma  con- 
taining resin  ducts. 
The  transverse  section  through  the  middle  of  the  involucral  scale  is 
elongated  in  shape  and  is  divided  into  an  upper  and  a  lower  part  by 
a  rather  broad  zone  of  sclerenchyma.  In  the  upper  part  beneath  the 
epidermis  is  a  palisade  layer  extending  to  the  edges  ;  but  the  lower 
part  has  no  palisade  cells,  but  contains  elongated,  thick-walled  cells, 
forming  large  intercellular  spaces.  Near  the  base  of  the  involucral 
scale  the  edges  are  free  from  palisade  cells,  but  contain  collenchyma. 
The  florets  are  small,  and  collected  into  many-flowered  heads ; 
those  of  the  outer  row  are  unisexual  and  ligulate,  while  the  disc 
florets  are  tubular.  The  latter  are  on  both  sides  covered  with  a 
cuticized  epidermis,  and  contain  a  slightly  developed  mesophyll 
with  compressed  cells,  which,  however,  are  wanting  in  some  parts  of 
the  corolla.  The  ligulate  florets  have  a  well-developed  mesophyll 
consisting  of  thin-walled  cells,  and  containing  yellow  oil  in  the 
intercellular  spaces.   Papillae  are  formed  on  both  sides  of  the  epidermis. 
Anthers,  gynaecium  and  the  seed  show  no  striking  characteristics. 
The  receptacle  has  rather  long  appendages  (Zotten)  which  differ  from 
those  of  most  composite  in  not  containing  vascular  bundles. 
Acetic  Acid  as  an  Antiseptic. — In  f  per  cent,  solutions,  acetic  acid 
has  given  favorable  results  as  an  antiseptic  in  gynecological  practice.  It  has 
several  advantages,  in  that  it  is  not  poisonous,  like  carbolic  acid ;  it  is  haemos- 
tatic, and  becomes  absorbed  readily.  It  does  not  injure  instruments  like 
bichloride  of  mercury  {Jour,  de  Med  de  Paris). — Med.  News,  Nov.  24,  1888. 
