Am.  Jour.  Pharm. 
January ,  1897. 
}  Alcohol  in  the  Titration  of  Alkaloids.  43 
cators  of  the  American  Pharmaceutical  Association,  Mr.  Kebler, 
in  his  instructions  to  the  committee  last  winter,  directed  the  use  of 
alcohol,  but  failed  to  note  his  experience  of  eighteen  months  ago 
(see  American  Journal  of  Pharmacy,  1896,  p.  667),  nor  did  he 
caution  the  members  against  the  use  of  commercial  alcohol.  Did 
he  assume  that  all  would  use  strictly  pure  alcohol,  and  did  he  use 
such  alcohol  in  his  own  work  done  for  the  committee  ?  This  fact 
should  have  been  noted  in  the  committee's  report. 
The  explanation  offered  in  the  writer's  paper  for  the  peculiar 
behavior  of  alcohol,  on  the  basis  of  electrolytic  dissociation,  was 
made  on  the  assumption  that  high-grade  commercial  alcohol,  known 
as  cologne  spirit,  could  scarcely  be  so  impure  as  to  account  for  the 
great  disturbance  observed,  especially  as  the  alcohol  employed  cor- 
responded quite  well  with  pharmacopceial  requirements,  and  since 
Ostwald  has  directed  attention  to  the  action  of  alcohol  on  color 
indicators.  Even  now,  when  using  strictly  pure  alcohol,  the  writer 
has  observed  that  in  a  mixture  of  only  alcohol  and  indicator  a  much 
larger  (two  to  four  fold)  quantity  of  alkali  solution  is  required  for 
the  characteristic  reaction  than  in  a  mixture  of  only  distilled  water 
and  indicator ;  moreover,  the  same  peculiar  behavior  towards 
tropseolin  was  observed  as  recorded  in  the  writer's  paper,  for  50 
c.c.  strictly  pure  alcohol  with  3  drops  of  a  very  sensitive  tropaeolin 
solution  failed  to  show  a  decided  acid  reaction  after  addition  of  4  5 
c.c.  H2S04.  This  latter  circumstance,  while  confirrning  the  un- 
fitness of  tropaeolin  as  an  indicator  for  alcoholic  titrations,  requires 
further  investigation. 
While  the  writer  regrets  his  misapprehension  of  the  causes  lead- 
ing to  the  observations  mentioned  in  his  paper  of  last  August,  and 
although  the  conclusions  then  arrived  at  have  now  been  shown  to  be 
partly  erroneous,  both  by  experiments  in  his  own  hands  and  by  the 
recently  published  reports  of  Mr.  Kebler,  one  good  result  has  at 
least  been  obtained,  namely,  to  show  the  wholly  unreliable  character 
of  commercial  alcohol  for  volumetric  work  and  to  direct  the  attention 
of  pharmacists  and  others  prominently  to  this  fact,  and  to  the  neces- 
sity for  purifying  all  alcohol  intended  for  such  work. 
Baltimore,  December  17,  1896. 
