Patton  says,  "There  is  no  shadow  of  doubt  that  the  bed-
bug transmits  the  disease,"  but  this  has  as  yet  not  been
definitely  proved.1  Further  studies  by  Nicolle  and  others
have  shown  that  the  dog  can  be  inoculated  with  the  type  of
the  disease  occurring  in  Tunis,  and  furthermore  that  the
disease  occurs  spontaneously  in  dogs  which  are  possibly  the
source  of  the  human  disease.  In  Tunis  only  children  have
so  far  been  observed  to  be  infected.  The  parasite  at  first
was  thought  to  be  somewhat  different  from  L.  infantum

1  Supplements  to  Third  and  Fourth  Reps.,  Wellcome  Research  Lab.,
Khartoum,  1908,  95;  1911,  150.
INFECTION  BY  INSECTS  403

but  the  two  forms  are  now  generally  believed  to  be  identical.
