^ja&SS?1-}  Rxpert  Testimony,  5 
partisan  advocacy,  are  badgered  into  it  by  the  unfair  efforts  of  cross- 
examiners  to  throw  doubt  and  obscurity  upon  their  direct  testi- 
mony. Unfortunately  these  efforts  are  sometimes  instigated  and 
directed  by  the  expert  witnesses  of  the  other  side. 
The  remedy  for  this  difficulty  lies  wholly  in  our  own  hands.  It 
will  not  do  to  abuse  the  lawyers  for  it,  however  much  they  may 
abuse  us  when  we  are  on  the  witness  stand.  Use,  abuse  or  misuse 
what  and  whom  they  will,  they  cannot  make  use  of  us  for  any 
purpose  for  which  we  refuse  to  be  made  use  of. 
A  third  order  of  difficulties  has  been  alluded  to,  but  may  now  be 
considered  more  fully.  It  is  often  assumed  that  expert  witnesses 
are  not  called  to  give  testimony  as  to  fact,  but  merely  to  express 
opinions,  and  that  hence  opinion  may  properly  be  set  against  opinion. 
This  is  but  partially  true.  Expert  witnesses  are  frequently  called  to 
express  opinions  upon  facts  which  they  must  themselves  first  testify 
to,  or  to  express  judgments  of  fact,  and  not  opinions  at  all — upon' 
investigations  that  they  have  themselves  made.  This  is  especially 
the  case  with  chemists  and  pathologists.  We  can  here  confine  our 
attention  to  chemists. 
A  chemist  or  pharmacist  may  be  asked,  for  example,  to  make 
certain  analyses  in  order  to  determine  the  purity  of  pharmaceutical 
products,  or  to  acertain  whether  foods  or  articles  of  commerce  have 
been  adulterated  or  have  had  foreign  substances  added  to  them  to 
color,  disguise,  or  preserve  them  ;  or  to  discover  whether  certain 
substances — sometimes  human  tissues — contain  poison.  He  submits 
the  suspected  articles  to  certain  physical  and  chemical  manipula- 
tions ;  examines  them  with  the  naked  eye,  with  the  microscope, 
with  the  spectroscope,  and  otherwise.  Upon  the  results  of  these 
examinations  he  forms  a  judgment.  When  describing  in  court  the 
methods  and  results  of  his  examinations,  it  will  be  generally 
admitted  that  he  testifies  as  to  facts.  How  about  the  judgment  he 
has  formed?  That  judgment,  when  stated  in  court,  is  commonly 
treated  as  an  expression  of  opinion.  In  reality,  it  is  a  judgment  as 
to  fact,  as  valid  as  any  other  judgment  as  to  fact  that  can  be  made 
the  subject  of  testimony.  It  differs  from  ordinary  judgments  in 
that  special  skill  and  knowledge  are  required,  first,  to  obtain  its  data, 
and,  secondly,  to  understand  their  significance ;  but  so  do  many 
other  judgments  that  we  never  think  of  treating  as  matters  of  opin- 
ion—which are,  indeed,  recognized  to  be  therefore  more  accurate — 
