530 
PROCESS  FOR  PREPARING  JAMES'  POWDER. 
Indeed  it  never  deserved  their  confidence,  being,  as  directed  in 
the  Pharmacopoeia,  an  almost  inert  substance. 
Dr.  Pearson  informs  us  that  all  the  parcels  of  James'  powder 
that  he  had  seen  would  be  called  white  powders,  but  no  two  of 
them  were  white  in  the  same  degree ;  they  had  either  "  a  shade 
of  yellow  or  stone  color,  and  none  were  perfectly  white,  or  so 
white  as  some  specimens  of  Pulvis  Antimonialis  of  the  shops. 
Some  parcels  had  a  brassy  taste,  others  no  taste.  Dr.  Pearson 
having  formed  a  powder  from  bone-ashes  and  crude  sulphuret  of 
antimony  possessed  of  properties  similar  in  kind  to  every  one  of 
those  ascertained  to  belong  to  James'  powder,  with  scarcely  any 
difference  in  the  degree  of  them,  considered  that  they  were  the 
same.  Beside  this  synthetic  proof,  he  adduced  the  evidence  of 
analysis,  and  made  experiments  in  proof  before  competent 
judges.  He  says,  "It  is  very  probable  that  no  degree  or  dura- 
tion of  fire  applied  in  open  or  close  vessels  alone  can  produce  a 
calx  of  the  same  kind  as  that  in  James'  powder,  nor,  perhaps 
can  such  a  powder  be  composed  by  fire  applied  in  close  vessels 
to  calx  of  antimony  mixed  with  calcined  bone ;  but  if  calx  of 
antimony,  duly  calcined,  be  mixed  with  calcined  bone,  and  ex- 
posed to  air,  in  a  due  degree  of  fire,  for  a  sufficient  length  of 
time,  and  then  a  still  greater  degree  of  fire  be  applied  to  it  in 
close  vessels,  such  a  compound  may  be  formed  as  James'  pow- 
der. .  .  .  No  such  white  powder  is  formed  by  a  mixture  of 
any  calx  of  antimony  and  bone  ashes,  exposed  to  any  degree  of 
fire  in  close  vessels,  without  previous  exposure  to  fire  and  air." 
Pearson  concludes  from  all  his  experiments  that  James'  pow- 
der consists  of  phosphate  of  lime  and  a  peculiar  calx  of  anti- 
mony, different  from  all  others,  composing  a  triple  compound  in 
the  proportion  of  about  57  parts  of  calx  of  antimony  and  43  of 
phosphate  of  lime,  or  a  double  compound  of  the  same  elements. 
The  admitted  medical  efficacy  and  the  high  price  of  James' 
powder  induced  the  various  colleges  of  physicians  to  introduce 
into  their  pharmacopoeias  a  process  for  imitating  it.  They  took 
for  their  guide  the  investigations  of  Pearson,  and  dictated  for- 
mulae Avhich  apparently  did  not  much  differ  from  the  prescription 
of  that  accomplished  physician.  This  preparation,  called  Pulvis 
Antimonialis,  proved  an  utter  failure,  having  neither  the  com- 
