Amjulyl;ri876arm,}  Powdered  Drugs  under  the  Microscope. 
99 
that  is,  starch  taken  from  the  grain  of  the  cultivated  wheat.  As  a 
matter  of  practice,  pharmacists  usually  sell  corn- starch  under  this  name. 
As  the  latter,  when  well  prepared,  is  an  excellent  article,  perhaps  supe- 
rior to  wheat-starch,  there  is  no  objection  to  this  substitution,  if  it  is 
well  understood. 
Wheat-starch  is  in  slender,  brittle,  irregular  prisms,  or  in  a  powder. 
It  is  of  a  dead-white  color,  odorless  and  insipid.  Like  most  starches, 
when  rubbed  between  the  fingers  it  crackles  slightly. 
The  grains  are  of  two  sizes,  with  but  few  intermediate.    The  larger 
ones  are  lens-shaped,  and 
present  only  indistinct  traces, 
if  any,  of  nucleus  and  rings. 
When  these  do  appear,  the 
former  is  central,  the  latter 
concentric.  They  are  from 
14//.  to  16//.  in  diameter. 
The  smaller  grains  are  spher- 
ical, and  usually  less  than 
3//.  in  diameter. 
The  starch  grains  of  rye 
and  of  barley  are  much  like 
those  of  wheat,  and  it  is 
sometimes  desirable  to  dis- 
tinguish them.  In  rye,  the 
larger  grains  are  from  16//. 
to  21//.  in  diameter,  and  have  frequently  a  distinct  star-shaped  nucleus, 
while  the  smaller  are  decidedly  smaller  than  those  of  wheat.  In  bar- 
ley, the  larger  grains  are  about  11//.  in  diameter,  with,  often,  rings  and 
nucleus,  while  the  smaller  grains  correspond  closely  to  those  of  wheat. 
Wheat  starch  is  a  prominent  constituent  of  "Imperial  Granum," 
"  Baby's  Cereal  Food,"  Ridge's  u  Cereal  Food,"  and  many  similar 
proprietary  substances.  They  are  powders  of  no  great  complexity, 
and  the  determination  of  their  constituents  would  be  excellent  prac- 
tice for  the  pharmacist  inexperienced  in  this  line  of  his  work. 
6.   CORN  STARCH  (Fig.  6). 
This  starch  is  derived  from  the  grain  of  corn,  and  comes  in  a  form 
like  that  of  wheat  starch.  Its  powder,  however,  is  glistening,  while 
that  of  wheat  is  dull. 
Fig.  5.  Wheat  starch. 
