AmAuSaf£m-}        A  Rejoinder  on  Solutions.  379 
A  REJOINDER  ON  SOLUTIONS. 
Editor  of  the  American  Journal  of  Pharmacy. 
Dear  Sir  : — In  the  July  number  of  the  American  Journal  of 
Pharmacy  I  observe  a  note  by  Mr.  Louis  Kahlenberg,  of  the  Uni- 
versity of  Wisconsin,  criticising  mildly  the  propriety  of  my  paper 
on  "  Change  of  Volume  when  Liquids  of  Different  Densities  are 
Mixed." 
Mr.  Kahlenberg  has  either  overlooked  or  failed  to  appreciate  the 
very  significant  statement  at  the  beginning  of  my  paper,  that  "  it 
has  been  known  for  some  time  that  solutions  of  salts  contract  when 
diluted  " — a  fact  of  which  I  was  fully  aware  at  the  time,  since  pre- 
vious to  writing  that  paper  I  had  written  a  "  Study  of  Solution," 
which  was  published  in  the  March  number  (1893)  of  the  Pharma- 
ceutical Review,  and  subsequently  copied  into  several  of  our  phar- 
maceutical journals,  which  "  study  "  was  essentially  a  digest  of  the 
recent  hypotheses  of  solutions  as  given  in  the  English  translation 
of  Professor  Ostwald's  masterly  work  on  "  Solution."  In  this 
article  note  was  also  made  of  the  thermal  and  optical  properties  or 
solutions,  and  full  credit  given  to  Professor  Ostwald's  publication. 
But  in  order  to  further  clear  up  the  misapprehension  which 
apparently  exists  over  the  purpose  of  that  paper,  kindly  allow  me 
to  briefly  state  the  circumstances  which  called  it  forth.  At  the 
visit  of  the  American  Pharmaceutical  Association  to  Boston,  in 
July,  1892,  I  became  engaged  in  a  friendly  controversy  with  the 
professor  of  pharmacy  in  a  sister  college  over  the  question  whether 
contraction  takes  place  when  glycerin  and  water  are  mixed. 
This  discussion  took  place  in  the  presence  of  a  score  or  so  of 
professors  representing  a  number  of  colleges  throughout  our 
country,  and  by  their  interest  in  the  discussion,  and  silence  as 
regards  the  points  involved.,  I  inferred  that  the  subject  was  new  to 
them,  and,  therefore,  that  the  fact  as  given  by  Professor  Ostwald 
was  not  well  known,  at  least  to  the  pharmacists  of  America.  On 
subsequently  learning  these  facts  through  reading  Professor  Ost- 
wald's book,  in  which  I  was  very  much  interested,  I  was  constrained 
to  write  and  publish  the  "  Study  of  Solution  "  for  the  purpose  of 
calling  the  attention  of  our  pharmacists  to  the  newer  theories  of 
solution,  and  subsequently  reinforced  this  by  the  paper  on  Con- 
traction, the  few  isolated  experiments  of  which  were  performed 
