THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
DECEMBER,  i8go. 
MICROSCOPICAL  AND  URINARY  NOTES. 
By  Hans  M.  Wilder. 
Illumination. — Perhaps  the  most  difficult  thing  to  learn,  in  the 
application  of  the  microscope,  is  the  proper  handling  of  the  light. 
Through  faulty  illumination  the  image  of  the  object  may  appear  dis- 
torted, or  some  of  the  minute  structure  may  be  entirely  obliterated, 
and  more  than  one  really  excellent  objective  has  been  condemned, 
because — through  faulty  illumination — it  did  not  do  what  it  was 
reasonably  expected  to  be  able  to.  What  influence  the  mode  of 
illumination  has  on  the  image  formed  can  be  shown  by  examining 
an  object,  with  the  appearance  of  the  minute  markings  of  which 
we  are  thoroughly  familiar,  with  a  wide  or  narrow  angle  of  light; 
central  or  more  o^less  oblique;  with  the  mirror  close  to  or  farther 
removed  from  the  stage.  If  we  examine,  for  instance,  a  slide  of 
potato  starch,  we  shall  see  the  individual  starch  grains  either  as 
solid  bodies  possessing  an  appreciable  thickness,  or  as  flat  oval 
discs,  or  as  depressed  discs  (something  like  soup  plates)  ;  according 
to  distance  of  the  mirror  from  the  slide,  the  mode  of  illumination 
and  a  very  slight  alteration  of  the  focus.  The  markings  will  alter 
their  appearance  more  or  less,  and  at  times  disappear  altogether; 
although  we  know  that  they  are  there,  and  that  our  objective  shows 
them  readily. 
Outfit.  — The  following  optical  battery  will  be  all  that  999  of  1 ,000 
pharmacists  ever  will  have  any  use  for.  A  i-inch  magnifier,  2-inch, 
2^-inch  and  i-inch  objectives,  2  eye-pieces,  condenser  on  stand 
(bull's-eye)  and  a  polarizing  apparatus.  These,  with  a  microscope 
stand,  nose-piece,  microtome  and  turn-table  will  cost,  at  the  lowest, 
593 
