402  A  Correction.  {Aml^wlm' 
amined.  (3)  That  aloin  contains  emodin,  to  which  its  laxative  pro- 
perty is  probably  due.  (4)  That  many  laxative  drugs,  such  as  senna, 
cascara  sagrada,  rhubarb,  buckthorn  bark,  besides  aloes,  owe  their 
laxative  property  to  this  substance  emodin  or  some  substance  like 
it,  derived  from  anthraquinone,  and  homologous  or  isomeric  with  it. 
Work  is  now  in  progress  to  show  the  exact  relation  of  anthraqui- 
none to  our  well-known  laxatives. 
(°  /jf  Oly  
v  ESTIMATION  OF  NITRITES:  A  CORRECTION. 
In  a  paper  that  appeared  in  the  June  number  of  this  Journal,  the 
undersigned  reported  a  method  for  the  valuation  of  amyl  nitrite 
and  spirit  of  nitrous  ether,  which  is  a  modification  of  a  method 
proposed  by  B.  Griitzner  for  the  estimation  of  nitrites  in  general, 
being  at  that  time  unaware  of  the  fact  that  a  similar  adaptation 
had  been  published  in  1897  by  F.  Dietze  (Sudd.  Apoth.  Ztg.,  1897, 
No.  35).  In  a  recent  number  of  that  periodical,  for  a  copy  of  which 
the  writer  is  indebted  to  Dr.  Dietze,  in  which  he  remonstrates 
against  the  failure  to  take  notice  of  his  work  and  the  German 
literature  on  the  subject.  Inasmuch  as  Dietze's  work  was  pub- 
lished in  a  journal  that  is  evidently  not  always  taken  cognizance 
of  by  those  periodicals  that  may  be  looked  upon  as  the  repositories 
of  everything  valuable  in  current  literature,  this  charge  is  hardly 
justifiable.  The  writer  has  no  desire  to  ignore  the  results  of  Ger- 
man investigators,  and  has  always  endeavored  to  give  credit 
wherever  it  was  due.  It  was  thought  justifiable  to  assume  that  all 
published  work  of  any  importance,  bearing  on  pharmaceutical- 
chemical  analysis,  would  be  found  in  such  standard  periodicals  as 
Chem  Ceniralblatt  or  Zeitsckrift  f.  anal.  Chcmie,  in  neither  of  which 
any  reference  to  the  subject  in  question  was  found. 
The  merit  of  first  applying  the  principles  involved  in  the  method 
to  the  estimation  of  nitrites  is  Griitzner's.  To  Dietze  belongs  the 
credit  of  having  first  adapted  the  method  to  the  valuation  of  spirit 
of  nitrous  ether,  and  to  E.  Buettner  (Sudd.  Apoth.  Ztg.y  1897,  No. 
98)  the  credit  of  confirming  its  usefulness  for  that  purpose.  The 
undersigned  presents  the  claim  of  having  independently  adapted 
Griitzner's  method  to  the  estimation  of  ethyl  and  amyl  nitrite,  at 
a  later  date,  and  of  furnishing  the  first  conclusive  proof  of  its 
accuracy  and  reliability.  Carl  E.  Smith. 
New  York,  July  7, 
