ANoVemberiS"}       Valuation  of  Drugs  and  Foods.  535 
for  instance,  -ioo  gramme  of  hsematoxylon  (logwood)  and  macerate 
it  with  500  c.c.  of  water  for  a  short  time,  the  solution  will  assume 
a  very  slight  purplish  color.  If  we  add  to  this  solution  a  few 
drops  of  ammonia  water,  it  becomes  a  cherry-red.  Comparing 
this  colored  solution  with  that  of  other  commercial  specimens,  dif- 
ferences in  intensity  are  observable,  which  indicate  the  comparative 
value  of  the  samples. 
(D)  In  endeavoring  to  ascertain  the  value  of  a  sample  of  crocus, 
carthamus  or  calendula,  we  find  that  light  straw-colored  liquids  are 
produced  on  using  o-ioo  gramme  of  any  of  these  drugs  and  mixing 
them  with  certain  proportions  of  water,  o-ioo  gramme  of  calen- 
dula requires  15  c.c.  of  water,  O-ICO  gramme  of  carthamus  requires 
100  c.c  of  water,  and  o*ioo  gramme  of  crocus  requires  500  c.c.  of 
water  to  produce  solutions  of  about  the  same  intensity  of  color. 
We  find,  moreover,  on  taking  o-ioo  gramme  of  each  of  these  drugs 
and  mixing  it  with  10  c.c.  of  alcohol,  that  the  crocus  alone  \s-im- 
mediately  colored,  producing  a  solution  the  color  of  which  is  about 
equal  in  intensity  to  the  aqueous  solution  already  described.  This 
is  a  rather  quick  method  for  getting  approximate  values  of  the  com- 
mercial articles.  It  should  be  noted,  as  in  the  preceding  cases  [A) 
and  that  the  yellow  color  of  the  aqueous  solutions  is  not  of 
exactly  the  same  shade  with  all  three  of  the  drugs.  The  yellow 
color  is  purest  with  crocus.  In  calendula,  there  is  a  slight  purplish 
tint,  and  in  carthamus  there  is  a  shade  of  color  between  calendula 
and  crocus. 
(E)  The  most  important  field  of  operation,  and  one  which  has 
the  greatest  promise  in  the  direction  already  indicated,  is  with 
drugs  that  contain  alkaloids  or  other  active  principles  with  which 
precipitates  or  colorimetric  reactions  may  be  obtained.  Operating 
with  quantities  of  drug  varying  from  -ioo  to  i-oo  gramme,  it  is 
soon  apparent  that  results  are  obtainable  which  may  have  as  great 
a  commercial  significance  as  the  results  obtained  by  the  more 
laborious  and  tedious  methods  usually  followed  by  analysts  and 
assayers.  The  number  of  specimens  operated  upon  has  not  been  as 
numerous  as  was  desired,  but  probably  sufficient  work  has  been 
done  to  justify  calling  attention  to  the  importance  of  another  line  of 
investigation  on  this  most  important  subject  of  the  valuation  of 
drugs  from  a  commercial  standpoint. 
It  seems  to  the  author  that  if  the  principles  of  chemical  assay 
