764  Value  of  Drugs  in  Internal  Medicine,  j  A^NJ0°^*i92hiarm' 
and  reliably  tested,  not  only  in  pharmacologic  laboratories  on  healthy 
animals,  but,  as  far  as  possible,  also  in  laboratories  of  experimental 
pathology  and  therapy,  on  animals  in  which  special  diseases  have  been 
induced,  before  we  shall  feel  justified  in  making  trial  of  them  in 
the  treatment  of  sick  human  beings. 
CLASSES  OF  PHARMACOTHERAPY. 
Now  that  physicians  generally  understand  that,  in  all  diseases 
or  pathologic  processes,  they  have  to  deal  with  modifications  of  nor- 
mal (or  physiologic)  processes  that  depend  on  definite  disease 
causes,  modifications,  moreover,  that  are  beyond  the  self -regulating 
capacity  of  the  organism  to  keep  within  those  limits  of  functional 
activity  that  we  observe  in  "health,"  the  internist  can  classify  his 
pharmacotherapeutic  efforts  according  to  the  kind  of  effect  he  de- 
sires to  produce.  Thus,  (1)  he  may  try  with  a  drug  to  remove  the 
cause  of  the  disease  or  to  render  it  harmless  (etiologic  pharmaco- 
therapy) ;  or  (2)  he  may  use  a  drug  that  will  help  directly  to  restore 
a  pathologically  disturbed  function  to  normal  ( functional  pharmaco- 
therapy) ;  or  (3)  he  may  administer  substances  that  will  aid  the 
organism  in  its  modes  of  reaction  against  the  disease-cause  (regu- 
latory pharmacotherapy)  ;  or,  finally,  (4)  he  may  employ  drugs 
merely  to  relieve  single  troublesome  symptoms  (symptomatic  phar- 
macotherapy). Internists  who,  after  thorough  and  complete  diag- 
nostic studies,  carefully  consider  these  several  indications  (etiologic, 
functional,  regulatory  and  symptomatic)  should  achieve  in  their 
pharmacotherapy  the  highest  possible  success. 
ETIOLOGIC  PHARMACOTHERAPY. 
Pharmacotherapy  is  seen  at  its  best  when,  through  the  use  of  a 
drug,  the  cause  of  a  disease  is  removed  or  rendered  harmless  (etio- 
logic pharmacotherapy)  before  the  patient  has  sustained  irreparable 
injuries.  The  organism  can  then  right  itself,  so  that  its  activities 
can  resume  their  normal  or  physiologic  course.  As  our  knowledge 
of  disease  causes  steadily  undergoes  increase,  ever  more  maladies 
will  be  made  accessible  to  etiologic  therapy.  Physicians  of  all  times 
have  considered  the  causal  indication  when  they  removed  harmful 
substances  from  the  stomach  by  emetics,  such  as  mustard  or  ipecac, 
or  from  the  intestine  by  purgatives,  such  as  castor  oil,  calomel  or 
magnesium  sulphate.   The  greatest  successes  in  causal  therapy  have, 
