XveZrerPi9i4m'l  Methods  for  Determination  of  Calomel.  511 
or  plants  of  common  parentage  could  be  distributed  for  the  produc- 
tion of  plants  to  be  used  experimentally.  If  under  such  an  agree- 
ment uniformity  of  treatment  throughout  the  processes  of  culture, 
curing,  and  analysis  could  be  secured,  comparison  of  results  would 
be  much  more  profitable  than  at  present,  and  the  tabulation  and  sum- 
marizing of  the  results  of  experimental  work  conducted  along  the 
lines  indicated  in  a  number  of  localities  would  permit  the  drawing  of 
conclusions  having  a  significance  far  greater  than  those  that  can  be 
reached  by  a  single  isolated  worker.  The  suggestions  here  offered 
contemplate  nothing  like  a  general  cooperative  investigation,  but 
rather  the  adoption  of  what  might  be  regarded  as  a  standard  method 
of  procedure  analogous  to  official  methods  of  analysis,  etc.  The 
tabulation  and  summarizing  of  results  might  well  follow  individual 
publication,  as  no  other  course  is  likely  to  give  satisfaction. 
In  conclusion,  I  wish  to  say  that  the  resources  of  the  experi- 
mental drug  gardens  of  the  Office  of  Drug-Plant  Investigations, 
Bureau  of  Plant  Industry,  are  open  to  any  school  of  pharmacy  desir- 
ous of  starting  a  medicinal  plant  garden,  as  are  also  the  facilities  of 
that  office  for  effecting  the  distribution  of  material  for  experimental 
purposes,  and  for  furthering  the  collection  and  compilation  of  data 
on  the  cultivation  of  medicinal  plants  under  great  diversity  in  con- 
ditions of  growth. 
Bureau  of  Plant  Industry, 
United  States  Department  of  Agriculture, 
August  18,  1914. 
A  STUDY  OF  SOME  OF  THE  METHODS  FOR  THE  DETER- 
MINATION OF  CALOMEL  IN  CALOMEL  TABLETS. 
By  J.  W.  Marden  and  O.  E.  Cushman. 
In  the  determination  of  calomel  in  calomel  tablets  there  is  a 
choice  of  several  methods  of  procedure.  Since  the  composition  of 
calomel  tablets  varies  considerably,  different  methods  apply  better 
to  some  samples  than  to  others,  and  care  must  be  exercised  in  select- 
ing a  method  which  will  give  correct  results  ;  many  fillers,  such  as  talc, 
sodium  bicarbonate,  gum  acacia,  confection  of  rose,  etc.,  are  often 
found. 
Possibly  the  most  widely  used  method  for  the  analysis  of  mer- 
curous  mercury  is  the  gravimetric  estimation  as  the  sulphide.1  In  this 
^Treadwell-Hall,  Anal.  Chem.,  vol.  ii,  p.  168;  Olsen,  Quant.  Chem.  Anal., 
P-  79- 
