Am.  Jour.  Pharm.  \ 
March,  1887.  J 
New  Crystalline  Acid  in  Urine. 
131 
disappeared,  and  nothing  remained  undissolved  but  the  small  quantity 
of  mercurous  chloride.  This  was  filtered  off,  washed  with  hot  water, 
dried  at  100°  O,  and  weighed.  From  this  weight  was  calculated  the 
percentage  of  mercurous  oxide.  The  mercuric  oxide  was  estimated 
by  passing  sulphuretted  hydrogen  through  the  filtrates  obtained  in 
the  previous  estimation,  after  nearly  neutralizing  them  with  alkali. 
The  resulting  sulphide  was  then  separated,  dried  and  weighed,  from 
which  weight  was  obtained  the  equivalent  weight  of  mercuric  oxide. 
The  following  are  the  results  of  100  parts  of  each  sample  : — 
HgO. 
H*aO. 
Fixed  matter. 
1  
98238 
•454 
•272 
2  
96-489 
•895 
1-007 
98- 1 74 
•532 
•371 
4  
98-237 
•746 
•416 
5  
97-692 
•268 
•212 
6  
96-895 
•853 
•954 
7  
97-787 
•758 
1-015 
The  deficits,  I  presume,  may  be  attributed  to  moisture  which  was 
not  separately  estimated,  except  in  one  or  two  cases,  as  a  check. 
It  will  be  seen  that  all  these  samples  are  very  satisfactory,  especially 
when  we  consider  the  amount  of  time  and  trouble  required  to  wash 
away  the  last  traces  of  a  bye-product  from  a  large  quantity  of  a  prep- 
aration. 
The  mercurous  oxide  may  be  due  to  the  mercuric  chloride  contain- 
ing some  soluble  mercurous  salt,  which  is  scarcely  probable,  or  else  it 
may  form  in  the  mercuric  oxide  on  keeping.*  A  freshly  made  sam- 
ple, prepared  by  myself,  gave  a  perfectly  clear  solution,  with  dilute 
hydrochloric  acid. — Phar.  Jour,  and  Trans.,  Feb.  5,  1887,  p.  640. 
CRYSTALLINE  ACID  IN  URINE   POSSESSING  MORE 
POWERFUL  REDUCING  PROPERTIES  THAN 
GLUCOSE. 
By  John  Marshall,  M.  ~D., 
Demonstrator  of  Chemistry,  University  of  Pennsylvania. 
In  the  early  part  of  last  November,  Prof.  Frank  Donaldson,  Sr.,  of 
Baltimore,  sent  for  examination,  to  Prof.  Tyson,  of  this  city,  a  urine 
which  contained  a  substance  having  strong  reducing  properties  much 
resembling  those  possessed  by  glucose.  After  Prof.  Tyson  had  fin- 
ished his  examination,  he  gave  the  remainder  of  the  urine  to  Prof. 
*On  exposure  to  light,  yellow  mercuric  oxide  becomes  dark  in  consequence 
of  partial  reduction  to  mercurous  oxide.    Editor  A.  J.  P. 
