1 
I  , 
^ '  1  tLj  ^  I  i-L*' 1  
266 
Stained  preparations 
The  description  is  given  almost  entirely  from  the  slides  which 
were  examined  in  Africa.  Like  Minchin,  we  have  found  that  the  ones 
which  were  left  to  be  stained  at  home  have  proved  to  be  practically 
useless. 
In  general,  the  trypanosomes  may  be  divided  into  the  two 
types,  long  narrow  ones,  and  broad  shorter  ones,  which  have  been 
mentioned  above. 
The  long  type  of  organism  is  chiefly  met  with  in  two  separate 
forms.  The  first  of  these  measures  from  30/1  to  40^  in  length  by 
17/1  to  2/1  in  width.  The  posterior  extremity  is  usually  rounded  or 
blmitly  angular,  while  the  anterior,  or  flagellar  extremity,  is  more  or 
less  acutely  drawn  out.  The  body  width  is  uniform  throughout  the 
greater  part  of  the  length  of  the  parasite,  so  that  it  bears  some 
resemblance  to  a  narrow  strip  of  ribbon.  The  nucleus  is  oval ;  as  a 
rule  occupies  the  whole  width  of  the  body,  and  does  not  present  any 
peculiarities  of  structure  other  than  in  a  few  instances ;  bein? 
composed  of  a  central,  deeply-staining  portion,  from  which  projects 
at  either  pole  a  more  loosely-built  wing.  The  blepharoplast  is  large, 
oval  or  round,  and  is  usually  placed  in  close  apposition  to  the  nucleus. 
More  generally  its  position  is  anterior  to  the  nucleus,  but  it  may  be 
lateral  or  posterior,  and  in  some  instances  is  separated  by  an 
appreciable  interval  from  it.  The  undulating  membrane,  as  a  rule, 
is  not  well  marked,  and  may  not  be  present.  The  flagellum  varies 
from  examples  in  which  a  distinctly  free  portion  of  some  length  is 
present,  to  those  in  which  none  is  discernible.  A  slight  club-shaped 
thickening  of  the  terminal  portion  of  the  free  flagellum  is  not 
uncommon,  and  in  one  or  two  cases  the  root  is  expanded  into  a  fan¬ 
like  arrangement  close  to  the  blepharoplast.  The  cytoplasm  stains  a 
darkish  blue  (Giemsa’s  stain),  and  may  contain  a  few  small  granules, 
though  commonly  it  is  free  from  these,  and  is  quite  homogeneous  in 
composition. 
The  second  variety  of  the  long  forms  is  an  extremely  narrow  and 
elongated  one,  which  may  measure  as  much  as  53  /t  in  length  by  only 
O' 5  4  in  width.  The  posterior  extremity  is  acute,  while  the  anterior 
end  is  drawn  out  very  gradually  along  the  flagellum.  The  nucleus  is 
long,  and  occupies  the  whole  width  of  the  body.  No  definite 
