^"^FetT^issr™"}        Borocitrates  and  their  Preparation.  65 
Russland,"  xix,  239).  Madsen  found  by  comparative  experiments 
upon  the  solubility  of  uric  calculus  in  solutions  of  lithium  benzoate 
and  magnesium  borocitrate  that  the  latter  salt  is  capable  of  dissolving 
almost  twice  the  quantity  of  urate  that  the  lithium  compound  can. 
Further,  when  a  small  dose  (1  gram)  of  the  sodium  or  magnesium  salt 
was  administered,  the  author,  after  several  hours,  succeeded  in  detect- 
ing boracic  acid  in  the  urine  by  the  flame  reaction.  In  this  case,  in 
order  to  prevent  the  volatilization  of  the  boric  acid  during  the  concen- 
tration of  the  urine,  the  operation  was  conducted  in  the  presence  of 
excess  of  potash  or  soda  solution. 
As  to  whether,  when,  after  administration,  the  boric  acid  occurs  in 
the  urine  it  is  combined  with  bases  or  free,  the  author  thinks  that  the 
following  experiment  shows  that  it  occurs  in  both  conditions.  After 
the  use  of  larger  doses  of  the  magnesium  and  sodium  compounds  (10 
to  15  grams  of  the  mono-,  di-  and  triborocitrates)  the  urine  was  evapo- 
rated to  perfect  dryness  and  then  extracted  with  absolute  alcohol. 
Boric  acid  could  be  detected  by  the  flame  reaction  both  in  the  alcohol 
and  the  residue.  Pure  boric  acid  is  soluble  in  alcohol ;  the  boric  salts, 
on  the  contrary,  are  not. 
Further  according  to  some  experiments  carried  out  by  Schwartz 
('^  Sitzungsbericht  d.  Dorpater  Naturforscher-Gesellscliaft"  (1879),  p. 
204),  magnesium  borocitrate  appears  to  be  a  stronger  antiseptic  against 
bacteria  than  pure  boric  acid,  and  indeed  he  proved  the  acid  salts  (those 
having  the  least  proportion  of  boric  acid)  to  have  a  more  energetic 
action  than  the  neutral  salt. 
According  to  Schwartz's  observations  the  mono-  and  diborocitrates 
of  magnesium  appear  to  decompose  in  the  presence  of  bacteria  and 
ferments,  and  the  author  thinks  that  it  may  be  assumed  that  in  this 
case  the  energetic  action  depends  upon  the  boric  acid  set  free  from  the 
compound  in  statu  nascendi. 
The  acid  salts  have  also  the  advantage  that  in  com^^arison  with  the 
triborocitrates  their  taste  is  more  agreeable  and  they  are  more  soluble 
in  water.  For  these  reasons  the  author  considers  the  mono-  and  dibo- 
rocitrates to  be  preferable  to  the  neutral  salts  for  therapeutic  use.  As 
w^ill  appear  by  analysis  reported  further  on,  the  preparations  most  fre- 
quently occurring  in  commerce  and  found  by  him  in  pharmacies,  are 
also  acid  salts. 
Like  the  salts  of  the  fixed  alkalies  and  alkaline  earths  there  exist 
three  chemically  constant  compounds  of  the  magnesium  borocitrates. 
5 
