230  Animal  Parasites  in  Man.  {AmM^£iarm' 
tightly  together.  Under  a  2/?>  ^ens  the  segment  may  be  studied, 
showing  the  uterus  stuffed  with  ova. 
To  Detect  the  Head. — This  being  the  portion  of  the  parasite's 
study  wherein  most  failures  are  experienced,  and  to  which  most 
importance  is  attached,  I  shall  cons'der  under  the  following  heads: 
(1)  Empty  the  bowels,  by  means  of  salines,  so  that  no  undigested 
food  remains  in  the  alimentary  tract ;  (2)  the  administration  of  a 
vermicide  ;  (3)  follow  in  four  to  six  hours  by  another  saline  ;  (4)  when 
it  is  observed  that  the  worm  is  beginning  to  escape  from  the  rectum, 
FiG.  2. — Tapeworm.    (1)  Natural  size  of  segments;  (2)  head  and  neck  (B. 
%)\  (3)  ova  (B.  Iv.,  Ye). 
the  patient  is  directed  to  occupy  a  comfortable  seat  where  the  worm 
can  pass  into  a  clean  vessel  containing  water;  (5)  all  important  is  it 
that  the  patient  sit  on  one  commode  from  the  time  he  observes  that 
the  worm  is  diminishing  in  size,  until  the  entire  worm  is  passed  ; 
(the  nearer  the  head,  the  smaller  are  the  segments),  when  within  a 
few  inches,  10  to  12,  of  the  head  the  worm  appears  as  a  pale  slightly 
flattened  thread  and  its  segments  are  not  distinct ;  (6)  the  head  is 
the  last  portion  of  the  worm  to  be  passed,  and  as  long  as  any  part 
of  the  parasite  is  protruding  from  the  rectum  the  probabilities  are 
that  the  head  has  not  yet  escaped. 
