30  Ehrlich's  Chemotherapy.  { Aj J^y',  m™' 
The  progress  made  in  the  chemotherapeutic  treatment  of  diseases 
produced  by  other  trypanosomes,  notably  that  of  the  "  sleeping  sick- 
ness," has  been  less  marked  up  to  the  present.  Something  has  been 
gained,  but  no  specific  drug  comparable  with  salvarsan  in  its  effi- 
ciency has  yet  been  found. 
It  is,  however,  recorded  that  in  Surinam  a  hospital  was  estab- 
lished to  treat  cases  of  another  tropical  disease  known  as  the  yaws. 
In  the  course  of  eight  days  three  hundred  and  twenty-eight  cases 
were  admitted,  and  at  the  end  of  fourteen  days  the  last  patient  was 
discharged,  cured,  and  the  hospital  had  to  be  closed. 
In  another  field  the  work  of  Ehrlich  has  led  to  procedures  which 
are  of  the  greatest  promise  in  the  study  of  the  processes  involved 
in  the  progress  of  medical  and  physiological  research,  namely,  so- 
called  "  vital  staining."  By  means  of  the  injection  of  dye-stuffs  into 
living  organisms,  it  is  possible,  because  of  the  selective  receptivity 
of  certain  tissues  or  parasites,  for  a  particular  color,  to  trace  the 
movement  of  bacilli,  and  to  watch  the  changes  which  they  occasion 
in  the  living  organism  itself.  The  same  procedure  is  employed  in 
the  study  of  healthy  tissue. 
To  Ehrlich's  clear,  analytical  mind,  exceptional  executive  ability, 
fine  technique,  and  extraordinary  industry  is  due  not  only  the  pro- 
cedure by  which  certain  particular  diseases  may  be  arrested,  but  a 
splendid  example  of  logical  attack  upon  other  similar  problems, 
which  offers  great  promise  for  the  future,  even  though,  as  in  the  case 
of  the  anti-toxins,  one  marked  success  may  not  be  at  once  followed 
by  others  of  equal  moment.  He  has  demonstrated,  in  a  way  which 
cannot  be  detailed  in  the  scope  of  this  article,  that  the  test-tube  ex- 
periments made  in  the  laboratory  with  a  particular  drug  upon  a 
special  parasite  cannot  be  alone  relied  upon  as  an  index  of  the  effect 
upon  it  of  the  same  drug  when  it  is  harbored  by  the  living  organism, 
since  the  action  is  essentially  modified  by  that  organism,  and  he  has 
advanced  theories  which  at  least  help  in  the  understanding  of  the 
possible  reasons  for  the  variations  in  behavior  thus  observed.  Even 
though  Ehrlich's  chemotherapy  may  not  be,  in  an  exact  sense,  a  "  new 
science,"  it  must  be  acknowledged  to  be  a  most  fruitful  and  helpful 
combination  of  the  principles  of  two  well-recognized  and  time- 
honored  sciences  for  the  benefit  of  mankind. 
