Amkarch  ^9i9m"  }    Chlor amine  Reactions  of  Proteins.  T71 
reactivity  of  the  amino  group.  As  an  industrial  operation  the 
chlorination  of  wool  had  long  been  known,  and  the  physical  modifica- 
tion produced  by  the  treatment  utilized,  but  the  persistence  of  the 
active  chlorine  in  the  treated  protein  was  considered  more  or  less 
as  a  technical  perversity  rather  than  a  fundamental  consequence  of 
the  reaction. 
Our  investigation  of  this  wide  subject  did  not  pretend  to  be  ex- 
haustive, and  many  "loose  ends"  were  left  both  in  the  qualitative 
and,  quantitative  aspects  of  the  subject.  Rasehig's  original  work 
related  only  to  the  monochloramine  group,  NH2C1,  or  in  the  case  of 
organic  amino  compounds  RNHC1,  and  the  circumstances  under 
which  the  second  hydrogen  atom  is  replaceable  by  halogen  were  left 
undecided.  This  uncertainty,  coupled  with  the  susceptibility  of  the 
products  to  progressive  decomposition,  led  to  the  failure  which  we 
subsequently  encountered  in  our  attempts  to  establish  an  easy  iodo- 
metric  method  for  the  estimation  of  amino  nitrogen  in  solution,  after 
removing  the  excess  of  hypochlorite  by  hydrogen  peroxide  and  the 
excess  of  the  latter  by  shaking  with  black  manganese  dioxide.  Posi- 
tive results  were  obtained  for  a  large  variety  of  compounds,  but 
their  variation  with  the  time  and  temperature  factors  caused  us  to 
abandon  hope  of  producing  a  workable  analytical  process. 
All  kinds  of  protein  derivatives  give  the  chloramine  reaction  re- 
gardless of  their  state  of  complexity  and  solubility.  Thus,  complex 
protein  colloids  like  silk  and  wool  combine  with  the  halogen  without 
entering  into  solution,  gelatin  in  aqueous  solution  is  percipitated  in 
the  form  of  an  insoluble  chloramine,  peptones,  albumoses  and  simple 
amino  derivatives  give  chloramine  compounds  which  are  soluble  in 
their  respective  degrees.  This  wide  range  through  all  grades  of 
colloids  and  colloidal  solutions  to  crystalloids  explains  the  observa- 
tion that  at  certain  stages  colloidal  chloramines  may  be  absorbed 
from  old  bleaching  liquors  by  vegetable  fibers.  Certain  observations 
made  in  those  early  days  are  worth  recalling  in  view  of  the  physio- 
logical interests  which  this  group  of  compounds  has  attained.  It 
was  suggested  at  that  time  that  the  persistent  odor  which  clings  to 
the  hands  after  immersion  in  hypochlorite  solutions  was  due  to  pro- 
tein chloramine,  and  this  suggestion  appears  to  have  been  fully  cor- 
roborated. Other  cases  of  "chemical"  odors  developed  in  bleached 
fabrics  have  been  traced  to  a  similar  cause. 
In  the  recent  clinical  publications  great  stress  has  been  laid  on 
the  alkalinity  of  hypochlorite  solutions  and  on  the  necessity  of 
