Am.  Jour.  Pharm.  \ 
March,  19 19. 
Note  on  Trypsin.  t 
173 
be  restored  uninjured  by  treating  with  an  "antichlor"  after  per- 
forming the  test.  The  localization  of  protein  in  plant  tissues  can  be 
demonstrated  in  the  same  way  by  the  treatment  of  their  sections  ; 
for  instance,  a  thin  slice  of  potato  shows  a  very  beautiful  network. 
Enough  has  been  said  to  indicate  the  wide  field  of  research  which 
is  open'  for  the  development  of  the  quantitative  relations  of  this 
interesting  reaction  in  the  light  of  recent  discoveries,  and  particu- 
larly for  the  study  of  the  functions  of  the  peculiar  form  of  "  active 
chlorine"  which  characterizes  the  group,  and  which  reacts  with 
iodides  in  the  proportional  equivalent  of  C1  =  I2.  What  are  the 
limits  of  its  oxidizing  activity?  For  example,  it  readily  oxidizes 
iodides,  arsenites  and  sulphites,  but  apparently  will  not  bleach  color- 
ing matters.  If  it  is  conceded  that  the  antiseptic  value  of  hypo- 
chlorites is  due  to  the  formation,  of  protein  chloramines,  what  is  the 
chemical  explanation  of  the  antiseptic  action  of  the  chloramines 
themselves  either  as  formed  in  the  tissues  or  as  applied  in  the  form 
of  pharmaceutical  preparations?  The  essential  characteristic  of  the 
group  is  instability,  and  its  relationship  to  the  highly  explosive  nitro- 
gen chloride  would  account  for  this.  C.  F.  Cross  patented  the 
preparation  of  methylene  chloramine  from  formaldehyde-ammonia,6 
which  is  also  somewhat  explosive,  but  it  is  recognized  that  certain 
classes  of  chloramines,  including  those  of  the  nitrogenous  colloids, 
are,  comparatively  speaking,  stable  compounds. 
NOTE  ON  TRYPSIN,  AND  A  NEW  METHOD  OF 
PURIFYING  ENZYMES.1 
By  Joseph  T.  Wood,  F.I.C. 
In  a  paper  entitled  "  A  new  method  of  isolating  trypsin,"  L.  Holz- 
berg2  refers  to  some  work  carried  out  by  Robertson,3  who>  found  that 
when  one  drop  of  a  saturated  solution  of  safranine  is  added  to  5  or 
10  Cc.  of  neutral,  or  very  faintly  alkaline,  0.5  per  cent,  solution  of 
Griibler's  trypsin,  a  light,  flocculent,  colored  precipitate  slowly  ap- 
pears and  gradually  settles.    It  was  assumed  that  the  substance  pre- 
6  Eng.  Pat.  15,303  of  1909;  ibid.,  1910,  976. 
1  Reprinted  from  Journal  of  Society  of  Chemical  Industry,  December,  1918. 
2  J.  Biol.  Chem.,  1913,  14,  335. 
3  /.  Biol.  Chem.,  1907,  2,  317. 
