296  Powdered  Drugs  under  the  Microscope  }  Amjftuirl8P76arm- 
endeavor  to  make  the  preparations  upon  the  market  conform  to  the 
requirements  of  the  u  Pharmacopoeia."  I  have  not  spoken  about  the 
etherial  strength  of  the  commercial  articles.  This  I  believe  to  be 
unnecessary  while  the  stuff  is  made  as  it  is,  for  even  if  the  full  amount 
of  nitrous  ether  is  present  when  the  article  is  sold,  it  will  not  long 
remain  reliable  while  in  contact  with  twenty-five  or  fifty  per  cent,  of 
water.  I  do  not  wish  to  be  understood  as  saying  that  every  manufac- 
turer is  making  adulterated  spirit  of  nitre.  I  believe,  however,  that 
one  hundred  pounds  of  the  adulterated  article  is  sold  upon  the  market 
to  one  pound  of  pure.  Let  our  retail  druggists,  over  the  country,  test 
the  preparations  upon  their  shelves  and  judge  for  themselves,  and  let 
us  endeavor,  in  some  manner,  to  reform  this  disreputable  business  ; 
for  such  I  must  consider  it  until  convinced  that  the  U.  S.  P.  is  wrong 
in  directing  the  specific  gravity  of  spirit  of  nitrous  ether  to  be  '837. 
POWDERED  DRUGS  UNDER  THE  MICROSCOPE. 
BY  MARK  W.  HARRINGTON,  M.A. 
Assistant  Professor  of  Botany  in  the  University  of  Michigan. 
[Continued from  page  246.) 
2.   TAPIOCA  (Fig.  2). 
A  starch  from  the  root  of  Manihot  utilissima,  a  poisonous  plant  of 
the  Spurge  family,  from  South  America  and  the  West  Indies. 
The  grains  are  unusually  compound,  the  two,  sometimes  three  or 
four,  grainlets  of  which  are  generally  separated  from  each  other  in  the 
preparation  of  the  article  for  market.  The  grainlets  differ  consider- 
ably with  the  direction  from  which  they  are  viewed.  From  the  side, 
they  appear  rounded  at  one  end,  cut  off  at  the  other,  and  contain  an 
apparently  conical  cavity,  of  which  the  nucleus  is  the  apex  and  the  flat 
side  of  the  grain  the  base.  Seen  from  the  end,  the  grains  appear  cir- 
cular, with  a  round,  central  nucleus.  The  lay- 
ers are  not  distinct,  though  sometimes  one  or  two 
can  be  made  out.  The  diameter  of  the  grains 
varies  from  itt.  to  16//. 
The  tapioca  of  the  markets  is  in  small,  white 
masses,  tough,  slightly  elastic,  odorless,  and  with 
a  slight  taste.  The  grains  of  starch  are  distorted, 
more  or  less,  by  the  heat  used  in  the  preparation 
of  the  article.  A  careful  examination,  however, 
will  show  many  grains  of  the  original  form. 
1  Figures  2  and  3  are  taken  from  Vogl's  "  Nahrungs-  und  Genussmittel "  j  the 
remainder  are  by  Miss  Reed. 
Fig.  2.  Tapioca 
starch.1 
