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sheep  and  goat.  One  inoculation  was  made,  O' 5  c.cm.  intraperitone- 
ally  into  a  white  rat,  without  result. 
Morphology  of  the  '  Scotsdale'  Trypanosome 
In  slides  made  from  the  infected  animals  at  Scotsdale,  it  was 
seen  that  the  trypanosomes  in  the  sheep  and  goat  differed 
morphologically  from  those  in  the  cattle,  and  the  occurrence  of  a  dual 
infection  was  suspected.  From  the  observations  on  Sheep  I,  how¬ 
ever,  it  was  shown  that  there  are  variations  of  the  same  parasite. 
We  may  commence  with  a  description  of  the  forms  seen  in  this 
animal. 
A.  'Long  form'.  In  fresh  preparations  the  parasite  is 
relatively  active,  crossing  the  field  with  a  steady  undulating  move¬ 
ment  of  the  flagellar  extremity,  a  passage  easily  followed  and  one 
creating  but  little  commotion  among  the  corpuscles.  When  arrested 
the  movements  become  more  vibratory.  On  no  occasion  was  the 
activity  manifested  by  J.  vivax  exhibited. 
In  stained  preparations  We  employed  Giemsa’s  solution  during 
the  earlier  part  of  our  work,  but  later  used  Leishman’s  stain  freshly 
prepared  in  methyl  alcohol  from  the  powder  made  by  Griibler.  This 
did  not  appear  to  deteriorate  as  did  Giemsa’s  solution,  although  this 
had  been  taken  out  in  small  lO'O  c.cm.  bottles. 
This  trypanosome  measured  from  20' 5  to  25'6  /i  (average 
24'74  /u)  in  total  length,  and  2  to  3  yu  (average  2'7  /i)  in  breadth.  A 
free  flagellum  was  present,  accounting  for  5-5  to  8' 5  //  (average 
6'3  yu)  of  the  total.  The  mean  of  a  series  of  measurements  is  as 
follows :  — 
Extremity  to 
Blepharoplast 
0-85 
Blepharoplast 
to  Nucleus 
6-39 
Nucleus 
Nucleus  to 
body  extremity 
8-0 
Free 
Flagellum 
The  posterior  extremity  is  rounded  or  bluntly  conical ;  cytoplasm 
stained  a  deep  pink  and  is  free  from  granules  or  vacuoles. 
Blepharoplast  round  and  prominent,  situated  about  its  own  length 
from  the  extremity.  Nucleus  compact,  but  not  deeply  stained, 
oval  in  shape,  measuring  approximately  3  x  r8  yti,  and  situated  about 
the  centre  of  the  body.  The  undulating  membrane  is  poorly 
developed,  existing  as  a  narrow  band,  or,  less  commonly,  showing 
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