^imbeS"1-}       Valuation  of  Drugs  and  Foods.  531 
understood  processes  involving  chemical  assay.  The  advantages 
of,  and  objections  to,  this  mode  of  the  valuation  of  drugs  are  too 
well  known  for  me  to  treat  of  them  at  this  time.  It  must  be  said, 
however,  that  from  here  and  there  have  come  evidences  that  the 
valuation  of  some  drugs  is  best  ascertained  by  other  means  than 
by  chemical  assay.  Dr.  Squibb  has  recommended  the  physiological 
test  for  aconite  and  its  preparations.  Remington  (Practice  of 
Pharmacy,  p.  1056)  says,  under  cantharides,  that  "  The  most  satis- 
factory test  of  cantharidin  is  its  vesicating  property."  Insect  pow- 
ders have  by  some  experimenters  been  tested  by  placing  a  number 
of  insects  under  the  direct  influence  of  the  powder.  A  few  years 
ago  the  author  showed  how,  in  some  instances,  as  in  the  adultera- 
tion of  cloves  with  pimenta,  starch,  etc.,  a  quantitative  microscopi- 
cal method  could  be  applied. 
The  question  as  to  what  is  the  quantitative  value  of  vegetable 
drugs  and  foods  is  such  an  important  one  that  the  author  has 
endeavored  to  broaden  its  scope,  and  to  bring  into  co-operation  all 
methods  and  tests  that  will  in  any  way  assist  in  the  solution  of  the 
many  problems  connected  with  it. 
The  methods  employed,  or  which  are  coming  into  use,  may  be 
conveniently  grouped  into  five  distinct  classes,  viz.: 
I.  Chemical  Methods. 
II.  Physical  Methods. 
III.  Microscopical  Methods. 
IV.  Biological  Methods. 
V.  Methods  involving  the  use  of  the  Polariscope  and  Spectro- 
scope. 
I.  CHEMICAL  METHODS. 
For  reasons  which  will  be  apparent  later  on,  the  author  does  not 
propose  to  consider  the  usual  chemical  assay  methods.  It  may  be 
stated,  however,  that  he  is  fully  aware  of  the  value  of  the  more  or 
less  definite  and  quantitative  results  which  may  be  had  by  appli- 
cation of  these  methods  in  the  examination  of  drugs.  It  may,  more- 
over, be  said  that  some  of  these  methods,  with  the  various  modifica- 
tions and  improvements,  will  undoubtedly  continue  to  be  employed. 
The  question,  nevertheless,  suggests  itself,  cannot  general  methods  be 
devised  which  may  not  only  be  performed  quickly,  but  which  will, 
compared  to  a  standard,  i.  e.}  the  best  quality  of  drug,  give  results 
which  will  have  a  certain  commercial  significance? 
