A^eceSrPhil9T-}         Powdered  Vegetable  Drugs.  619 
which  are  15  fi  thick;  characteristic,  nearly  isodiametric,  thick- 
walled  stone  cells,  with  but  small  lumen  ;  the  cells  of  embryo  con- 
tain oil  and  aleuron.  The  amount  of  seed  in  powder  is  determined 
by  number  of  oil  globules  and  fragments  of  seed  coat.  The  U.S.P. 
directs  only  pulp,  not  seeds  or  epicarp. 
550.  Cydonuim. — Without  starch  or  calcium  oxalate;  character- 
istic seed  coat  consists  of  an  outer  layer  of  clear  mucilage  cells,  as  in 
linum,  beneath  these  are  cells  with  thick  walls  and  contain  a  pigment 
reacting  like  tannin  ;  parenchyma  contains  oil,  protein  and  tannin. 
551.  Linum.— Numerous  fragments,  possessing  characteristic 
tabular  reddish-brown  pigment  cells  ;  when  seen  in  surface  view 
(15  x  30  /x)  associated  with  small  yellowish-colored  stone  cells; 
mucilage  layer  prominent,  being  the  outer  epidermis ;  relatively 
thin-walled  parenchyma,  containing  oil  and  aleuron. 
552.  Pepo. — See  No.  527. 
f  No  starch,  tannin  or  crystallizable  carbo- 
hydrate ;  mucilage  layer  not  so  prominent 
as  in  cydonium  or  linum ;  much  oil  and 
aleuron  (latter  in  small  grains)  ;  not  infre- 
quently find  complete  transverse  sections  of 
seed  coat  in  the  powder.  In  Sinapis  alba 
the  coat  consists  of  hexagonal  epidermal 
cells  (45  fi) ;  then  follows  a  sub-epidermal 
I  collenchyma,  a  light  yellowish  or  color- 
0.      .  ,T.         less  pigment  layer  and  a  layer  of  stone  cells 
554.  Sinapis  Nigra.     ,„  x      '     „     r    ,  .  . 
(8  x  10  ^),the  walls  of  which  are  4  ^  thick. 
In  Sinapis  nigra  the  unequal  hexagonal 
epidermal  cells  are  larger,  45-70  //,  the  pig- 
ment layer  is  reddish- brown  and  stone  cells 
are  about  as  in  Sinapis  alba.     Both  mus- 
I  tards  are  turned  blood-red   in  color  by 
I  H2S04.    Likely  to  find  fragments  of  tur- 
[  meric  in  yellow  mustard. 
555-  Staphisagria. —  Characteristic  fragments  of  seed  coat  with 
brown  pigment  and  possessing  prominent  hexagonal  stone  cells 
(80  fx  wide)  with  thick  walls  (20  /x) ;  long  spindle-shaped  cells,  such 
as  occur  in  delphinium  are  present;  parenchyma  contains  oil  and 
aleuron. 
556.  Sir amonii  Semen. — Peculiar  greenish  fluorescence  of  mount 
553-  Sinapis  Alba 
