92  Detection  and  Determination  of  Alcohol  {Ami™'$grm' 
Deducting  3*6  from  6*3,  we  have  2*7  as  the  percentage  of  alcohol 
added. 
Alcohol  is  said  not  to  suffer  decomposition  in  presence  of  pure  water. 
To  confirm  this,  a  sample  of  well  boiled  water  had  *i  per  cent,  of 
alcohol  added,  and  determinations  made  daily.  After  ten  days  the 
quantity  of  alcohol  was  found  undiminished.  An  impure  tank  water, 
to  which  -i  per  cent,  of  alcohol  had  been  added,  did  not  contain  a  trace 
twenty-four  hours  afterwards.  The  presence  of  decaying  organic 
matter  of  all  kinds  has  this  effect,  and  no  doubt  this  reaction  is  in  some 
degree  a  measure  of  the  quality  of  awater. 
Rajewsky  (Pfluger's  "Archiv,"  xi.,  122,  "Abs.  Y.  B.  P.,"  1876,  125) 
when  investigating  the  action  of  alcohol  upon  the  system,  its  passage 
into  the  brain  and  muscle,  and  the  length  of  time  which  it  remains 
there,  came  to  the  conclusion  that  the  iodoform  test  is  either  not  appli- 
cable to  the  detection  of  alcohol  in  the  tissues  or  that  alcohol  is  a  nor- 
mal constituent  of  brain  and  muscle.  I  have  applied  the  aldehyd 
test  to  a  number  of  infusions  of  fresh  muscle,  or  rather  to  the  distil- 
late from  this  infusion,  but  have  failed  to  detect  the  slightest  trace  of 
alcohol. 
The  chromic  acid  reaction  is  still  often  quoted  as  a  test  for  alcohol 
in  the  urine,  but  as  shown  by  Chaumont  (abs.  Y.  B.  P.,  1885,  147) 
the  test  is  not  to  be  relied  upon  even  when  applied  to  the  distillate. 
A  number  of  experiments  were  tried  with  various  samples  of  urine, 
with  and  without  the  addition  of  alcohol.  By  adding  a  sufficient  quan- 
tity of  bichromate  to  oxidize  all  the  oxidizable  matter  present  in  the 
urine  good  quantitative  results  were  obtained.  By  distilling  the  urine 
and  estimating  the  alcohol  in  the  distillate,  the  results  were  all  much 
too  low,  but  when  about  a  gram  of  ferrous  sulphate  was  added  to  the 
urine  previous  to  distillation,  the  results  were  much  more  approximate. 
Should  the  urine  contain  albumen  it  must  be  distilled  and  the  distillate 
examined,  but  otherwise  equally  good  results  are  obtained  without  dis- 
tillation. After  partaking  of  an  alcoholic  fluid,  distinct  traces  of  alco- 
hol are  found  in  the  urine  two  hours  afterwards.  The  quantity  (after 
taking  12  cc.  of  absolute  alcohol)  in  the  urine  two  hours  after  was 
about  02  per  cent.,  and  about  the  same  proportion  was  found  ten 
hours  afterwards,  and  traces  were  present  for  upwards  of  twenty-four 
hours.  Forty  hours  after  no  alcohol  could  be  detected.  From  the 
quantity  of  urine  excreted,  the  results  of  two  determinations  went  to 
