AmNov  r'i92iarm* }  Value  of  Drugs  in  Internal  Medicine.  765 
however,  been  achieved  by  using  drugs  that  kill  living  animal  or 
vegetable  parasites  within  the  body,  or  that  drive  them  from  the 
body  into  the  world  outside.  The  use  of  oleoresin  of  male  fern 
against  tapeworm,  of  santonin  against  roundworms,  and  of  oil  of 
chenpolium  against  hookworms,  are  paradigms  of  antiparasitic  phar- 
macotherapy. The  parasites  of  malaria  were  killed  by  the  quinin 
contained  in  cinchona  long  before  we  knew  that  the  malarial  fevers 
were  parasitic  in  origin.  Pathogenic  amebas  in  the  intestine  can  be 
killed  off  by  means  of  emetin  hydrochlorid.  The  fungi  that  cause 
blastomycosis  and  sporotrichosis  die  when  subjected  to  the  influence 
of  the  iodids.  Noteworthy  triumphs  have  recently  been  scored  also 
by  etiologic  chemotherapy  directed  against  certain  parasites  (try- 
panosomes,  spirochetes  and  spirilla)  that  cause  African"  sleeping 
sickness,  syphilis,  and  relapsing  fever.  Through  prolonged  experi- 
mental work,  parasiticides  have  been  discovered  that  have  a  greater 
affinity  for  and  toxic  effect  on  trypanosomes  and  spirilla  than  on  the 
body  cells  and  organs ;  in  other  words,  poisons  that  are  more  par- 
asitotropic than  organotropic  can  now  be  used  to  kill  certain  invading 
micro-organisms  without  too  much  injury  to  the  invaded  host.  . 
Arsphenamin  and  neo-arsphenamin  help  us  greatly  in  the  fight 
against  syphilis,  and  are  undoubtedly  valuable  additions  to  our 
pharmacopeia.  With  further  studies  of  the  parasitotropic  qualities 
of  various  arsenical  and  antimonal  compounds,  we  can  reasonably 
hope  for  satisfactory  means  of  control  of  a  series  of  tropical  diseases 
that  up  to  recent  times  have  defied  the  efforts  of  therapists. 
In  the  antiparastic  treatment  of  diseases  of  bacterial  origin,  ex- 
perimental chemotherapy  has  thus  far  been  baffled.  This  does  not 
mean,  however,  a  permanent  defeat.  There  is  much  to  encourage  in- 
vestigators to  continue  their  search  for  internal  disinfectants  that 
may  be  safely  used.  The  body  fluids  and  the  body  cells  contain, 
and  manufacture,  substances  that  can  kill  bacteria.  The  chemical 
constitution  of  these  bactericidal  substances,  we  can  feel  sure,  will 
ultimately  be  discovered ;  the  substances  will,  later,  be  made  syntheti- 
cally and  utilized  in  therapy.  Moreover,  toxic  bacteriotropic  sub- 
stances that  are  foreign  to  the  organism  and  innocuous  for  it  will  also 
doubtless  be  found  and  used.  We  already  know  that  ethylhdrocuprein 
will  kill  puneumococoi,  though  its  deleterious  effect  on  the  optic 
nerve  makes  it  unsafe  as  yet  as  a  therapeutic  agent.  But  who  knows 
how  soon  some  enterprising  experimental  chemotherapist  may  find  a 
