592  Assay  of  Hypochlorite  Solutions,  {Am-^Tm1^rm" 
motives  for  infliction  of  pain,  when  pain  is  actually  inflicted,  than 
merely  healthful  exercise  and  transient  enjoyment. 
Is  it  logical,  therefore,  to  attempt  legislation  to  limit  and  restrict 
a  form  of  research  so  valuable  to  mankind? 
NOTES  OX  THE  ASSAY  OF  HYPOCHLORITE 
SOLUTIONS.1 
By  Frank  X.  Moerk,  Ph.M.,  and  Ralph  R.  Foran,  P.D. 
PHILADELPHIA,  PA. 
Our  attention  was  recently  called  by  Dr.  J.  AY.  Stunner  to  a  dif- 
ficulty in  the  assay  of  a  sample  of  Dakin's  solution,  in  which,  after 
obtaining  the  end  reaction  the  blue  color  returned  and  addition  of 
volumetric  solution  had  to  be  made  repeatedly  until  a  permanent  end 
reaction  was  obtained. 
The  Dakin's  solution  in  question  was  made  by  passing  4.8  Gms. 
("or  about  1,600  Cc.)  of  chlorine  gas  into  a  solution  containing  14,1 
Gms.  of  anhydrous  sodium  carbonate  (or  the  equivalent  of  mono- 
hydrate  or  decahydrate)  per  liter.  Should  the  preparation  be  too 
strong  it  is  diluted  with  a  solution  containing  1.4  per  cent,  of  an- 
hydrous sodium  carbonate. 
The  chemical  reaction  involved  is 
2Na2COs  +  Cl2  +  HoO  =  XaCIO  +  NaCl  +  2NaHCOs, 
from  which  can  be  calculated  that  4.8  Gms.  of  chlorine  will  require 
14.332  Gms.  anhydrous  sodium  carbonate  and  will  yield  5.004  Gms. 
sodium  hypochlorite  and  also  that  14. 1  Gms.  anhydrous  sodium  car- 
bonate will  require  4.717  Gms.  chlorine  and  yield  4.954  Gms.  sodium 
hypochlorite. 
The  directions  for  the  assay  of  the  solution  are  as  follows : 
Measure  10  Cc.  of  Dakin's  solution  into  a  beaker  or  Erlenmeyer 
flask  containing  50  Cc.  of  water,  add  5  Cc.  of  a  10  per  cent,  potas- 
sium (or  sodium)  iodide  solution  and  2  Cc.  of  glacial  acetic  acid. 
Run  in  decinormal  sodium  thiosulphate  solution  until  decolorization 
is  complete,  using  starch  solution  as  indicator. 
1  Read  at  the  annual  meeting  of  the  Pennsylvania  Pharmaceutical  Asso- 
ciation, Buena  Vista,  June,  1919. 
