248  Commercial  Hypophosphorous  Acid.    {Am  M°a"r;il8h7arm' 
of  calcium  is  to  a  certain  extent  soluble  in  hypophosphorous  acid,  for 
I  verified  this  by  an  experiment,  the  question  arises,  "  Is  the  presence 
of  calcic  oxalate  likely  to  have  any  deleterious  effects  ?  "  Supposing 
the  sample  to  be  required  for  the  preparation  of  a  compound  syrup  of 
the  hy  pophosphites  containing  the  calcium  salt,  it  would  lead  to  endless 
trouble  to  keep  a  presentable  syrup.  Even  if  it  were  contained  as 
free  oxalic  acid  it  would  be  more  easily  got  rid  of  (as  it  would  be  all 
thrown  out  at  once)  than  by  the  slow  process  of  precipitation  which 
would  go  on  for  months,  as  in  presence  of  a  less  acid  solution  the 
calcic  oxalate  slowly  separated.  If  it  were  required  for  dispensing 
purposes  it  would  when  diluted  gradually  deposit  its  impurity. 
Again  the  quantity  of  impurity  introduced  into  the  system  would 
amount  to  something  considerable  in  time,  were  the  medicine  persis- 
ted in.  In  short,  the  acid  is  not  likely  to  recommend  itself  as  a  mode 
of  exhibiting  the  hypophosphorous  radicle  until  the  commercial  article 
is  to  be  obtained  purer.  I  have  never  personally  come  across  a  sample 
of  the  commercial  drug  that  did  not  deposit  more  or  less  after  being 
kept  for  a  week  or  two. 
Mr.  A.  E.  Robinson,  in  a  paper  read  before  the  British  Pharma- 
ceutical Conference,  in  1885,  suggested  the  use  of  this  acid  as  a  pre- 
servative agent,  for  a  concentrated  solution  of  ferrous  iodide,  specify- 
ing that  care  must  be  taken  that  the  acid  should  contain  no  oxalic 
acid.  Then  these  samples,  whether  used  as  a  preservative  for  ferrous 
iodide,  bromide  or  chloride,  would  not  do.  It  was  thought  likely 
that  the  more  concentrated  solution  would  give  evidence  of  the  presence 
of  phosphorous  acid,  but  this  was  not  so,  except  in  one  case,  and  the 
volumetric  and  gravimetric  estimations  taken  conjointly  confirm  this. 
The  high  specific  gravity  of  sample  C  is  due  to  excessive  quantity  of 
lime  salt  it  contained.  That  the  neutralizing  power  of  the  samples  is 
lower  than  their  reducing  power  is  also  borne  out  by  the  same  fact. 
The  only  inquiry  suggested  by  the  quantitative  estimation  is,  "  Whether 
a  10  or  30  per  cent,  sample  should  be  used  when  acid  hypophosphorous 
is  simply  ordered  ?JJ  The  quantitative  determinations  proved  one 
thing,  however,  which  would  otherwise  have  remained  a  matter  of 
doubt,  namely,  that  phosphorous  acid  was  absent  almost  entirely  from 
the  samples. 
This  was  contrary  to  my  preformed  judgment,  having  thought  that 
at  all  events  the  more  concentrated  solutions  would  contain  appreciable 
quantities.    Had  there  been  another  week  at  my  disposal  before  com- 
