n6 
Synthetic  Chemicals. 
(Am  Jour.  Fnarm. 
I      March,  1900. 
portions  of  other  chemicals  as  impurities  incident  to  the  process 
of  preparation,  some  of  which  have,  moreover,  decided  therapeutic 
properties  of  their  own,  that  they  cannot  possibly  be  considered  as 
pure  silver  or  mercury.  As  these  preparations  have  considerable 
interest  in  themselves,  and  much  attention  has  been  paid  in  the 
journals  recently  to  metals  in  the  colloidal  state,  we  give  the  results 
of  analysis  in  full.  A  large  percentage  of  the  metals  had  reverted 
to  the  ordinary,  or  insoluble  form.  According  to  the  latest  theory 
in  regard  to  colloidal  metals  they  are  in  a  state  of  emulsion,  as  it 
were,  and  the  impurities  are  necessary  to  keep  the  minute  particles 
of  the  metal  in  suspension. — {Jour.  Soc.  Chem.  Ind.,  1899,  18-1129.) 
COI,I,ARGOI,UM. 
Per  Cent. 
Water  (loss  at  ioo°  C.)   2*32 
Silver  (Ag)   84-05 
Iron  (Fe)  1-39 
Equivalent  to  ferrous  tartrate   5*06 
Ammonia  (NH3)  2*25 
Equivalent  to  ammonium  tartrate   7*42 
98-85 
Soluble  in  water  25-28 
Insoluble  in  water   7472 
TOO'OO 
HYRGOUJM. 
Mercury  (Hg)   70*47 
Tin  (Sn)  8*60 
Equivalent  to  colloidal  stannic  acid   12*22 
Ammonia  (NH3)  3-22 
Equivalent  to  ammonium  citrate  .  .   15 '33 
Water,  etc.  (by  difference)   1  -98 
100*00 
Diuntin  represents  a  class  of  preparations  in  which  the  applica- 
tion of  the  usual  test  of  a  definite  chemical  formula  would  appear  to 
entitle  them  to  exemption.  It  is  prepared  by  mixing  solutions  of 
the  sodium  salt  of  theobromine  and  sodium  salicylate  in  the  proper 
molecular  proportions  to  form  a  double  salt,  and  evaporating  to 
dryness.  The  manufacturers  claim  that  a  definite  compound  is  pro- 
duced, but  the  combination,  if  any,  is  a  very  weak  one.  The  pres- 
ence of  free  theobromine  is  also  shown  by  its  extraction  with  a 
solvent. 
