402  The  Pharmacist  and  the  Microscope. 
with  the  spirit  of  the  State  Boards  in  giving  the  candidates  as  practi- 
cal examinations  as  may  be  possible.  The  microscope  must,  in  this 
province,  be  used,  as  only  by  means  of  it  can  one  determine  most 
of  the  powdered  drugs  and  pronounce  on  the  quality  of  all.  By 
means  of  the  microscope,  drugs  of  different  origin  may  readily  be 
determined,  as  the  various  sarsaparillas,  sennas,  ipecacs,  etc. 
(3)  As  a  Preliminary  Step  in  the  Study  of  Plant  Constituents. — 
The  microscope  is  of  undoubted  service  as  a  preliminary  step  in  con- 
ducting chemical  examinations  of  drugs.  The  nature  of  inorganic 
substances  (as  CaC03,  CaC204,  Si02,  etc.)  may  readily  be  detected. 
The  nature  of  some  carbon  compounds  (as  starch,  sugar),  and  active 
principles  (as  oils,  resins,  tannins  or  other  substances)  may  be 
detected  qualitatively. 
(4)  In  Determining  the  Relative  Value  of  Drugs. — It  not  infre- 
quently happens  that  two  drugs  of  different  origin  or  habitat  are 
used  in  medicine,  and  that  the  cheaper  contains  the  larger  percent- 
age of  active  principles.  A  chemical  assay  may  be  resorted  to ;  but 
when  purchasing  a  small  quantity  of  a  drug  this  might  not  pay. 
By  means  of  the  microscope,  however,  an  approximate  comparison 
may  be  instituted,  even  quantitative  results  may  be  obtained,  as 
has  already  been  shown,  and  will  be  further  demonstrated  in  a 
forthcoming  paper.  This  applies  not  only  to  powdered,  but  also  to 
crude  drugs.    The  following  instances  may  be  cited  : 
(a)  Gingers. — The  African  ginger  is  cheaper  than  the  Jamaica 
ginger,  but  the  former  contains  more  secretion  cells,  which  are 
about  the  same  size  in  both.  Hence,  the  African,  though  cheapest, 
assays  a  higher  percentage  of  oleoresin. 
(b)  Buchus. — The  short  buchu  is  cheaper  than  the  long  buchu, 
but  resembles  the  former,  and  contains  much  larger  and  more 
numerous  secretion  reservoirs  than  the  latter ;  hence  the  "  short 
buchu  "  assays  more  oil  than  the  other. 
(5)  In  Determining  Loss  of  Active  Principles. — It  is  possible  in 
some  cases,  without  resorting  to  a  chemical  assay,  to  determine 
whether  the  active  principles  have  been  removed.  This  is  notably 
so  in  drugs  that  contain  alkaloids,  secretion  reservoirs  or  secreting 
hairs,  as  cinchona,  ginger,  cloves,  or  any  labiatse. 
(6)  In  Determining  Identity  and  Quality  of  Spices  and  Foods. — 
Since  the  introduction  of  spices  in  a  powdered  condition  into  the 
household  there  has  been  the  most  flagrant  kind  of  adulteration 
