242  Powdered  Drugs  under  the  Microscope.  \Amj^J7^rm' 
that  amylaceous  matter  is  present.  The  microscope,  on  the  other 
hand,  can  easily  distinguish  between  them. 
One  great  advantage  in  the  use  of  the  microscope  is  the  readiness 
with  which  results  can  be  obtained  from  it.  But  a  moment  is  needed 
by  the  skilled  microscopist  to  distinguish  the  various  starches,  or  to 
analyze  the  various  proprietary  flours,  prepared  foods,  farinas,  etc.  ; 
and  even  such  complicated  mixtures  as  the  tooth-powders  can  be 
unraveled  in  a  short  time.  The  chemist  would  have  to  spend  much 
time  over  the  latter,  if,  indeed,  he  could  succeed  in  performing  it 
at  all. 
For  the  work  contemplated  in  these  papers  a  complicated  and  costly 
instrument,  with  all  the  modern  expensive  appliances,  is  not  required; 
an  inexpensive  microscope,  with  a  magnifying  power  of  200  or  300 
diameters,  is  sufficient.  One  of  the  cheaper  compound  microscopes, 
with  an  inch  objective,  can  be  made  to  answer,  a  half  inch  or  a 
quarter  inch  objective  should  be  added  as  soon  as  practicable,  as  it 
will  be  sometimes  needed.  They  can  be  obtained  of  any  reputable 
maker  or  dealer  at  prices  varying  from  $25.00  to  $150.00,  depending 
on  the  character  of  the  workmanship  and  number  of  objectives  and 
accessories. 
Instructions  concerning  the  use  of  the  microscope  must  be  looked 
for  in  books  devoted  to  that  subject.  With  cleanliness,  care  and 
some  patience  any  one  can  use  the  instrument  successfully.  When 
the  tissue  of  a  drug  is  to  be  examined,  it  should  be  softened  by  soaking 
in  water,  or  some  other  fluid,  and  then  as  thin  sections  as  possible  be 
taken  in  several  directions.  The  sections  can  be  transferred  to  a 
glass  slip  by  means  of  a  camel's  hair  brush.  They  should  be  deposited 
in  a  drop  of  water  and  covered  by  thin  glass  when  they  are  ready  for 
examination.  If  greater  transparency  is  required,  the  sections  can  be 
placed  in  glycerin ;  still  greater  transparency  can  be  obtained  by  placing 
dry  sections  in  Canada  balsam.  If  a  powder  is  to  be  examined,  a 
very  small  part  of  it  should  be  placed  on  the  glass-slip  in  water, 
glycerin  or  Canada  balsam. 
II.  STARCHES. 
The  starches  form  powders  of  a  simple  nature,  with  which  the 
unpractised  observer  will  do  well  to  begin.  They  vary  very  much 
in  form,  size  and  structure,  and  to  some  extent  in  chemical  charac- 
teristics. 
