12 ^ 
III. THE TRYPANOSOMES OF NATURALLY-INFECTED DOGS 
The forms seen in all three animals are the same. The lr>'pano- 
somes measure from 20*25 to 28‘9/i in length, and from 1*5 to 
2'5yu in width. The protoplasm stains pink with Gicmsa, vacuoles 
and granules were inconstant ; the posterior extremity is most 
commonly pointed. The nucleus is situated towards the antenor 
part of the body, and varies m shape from a round to an elongate oval, 
the former taking a deeper stain than the latter. The hlcpliaroplast 
is rounded, usually terminal, but may be removed from the posterior 
extremity by as much as 2*5/1. A wcII-cievclo|jed undubling 
membrane is present, and the rim is continued as a flagellum, wluch 
varies from 3 to lO/i in length, and is accompanied, in the short loras 
at least, by a prolongation of the cytoplasm. Those carr>-ing a start 
flagellum correspond in type to the so-called ' female ' forms, and the 
long flagellar forms to the ‘male* of other trypanosomes. It would 
be impossible to assert that these 'females’ arc not the ‘stumpy' 
o . dimorphon, which are somewhat larger than normal 
any 
ment maH were not encountered ; the smallest mcasoK- 
which re ^ In the two guinea-pigs, the trypanosomes 
30.; in the snluer forms 
depend mainlv short. The variations in length noted 
fairly constant IZ 
any stage of the infection. ' not seen at 
fn rats no forms * i_ > 
measured from 21 to 30/1 and f 
distinct flaeellar 2/i in width. There is a 
guinea-pigs only in beinp ''^*^** f^^ni those seen « 
variations comparaL ^re monomorphic in so far as no 
fo™s were seL '‘^dpole’ and 'long' 
of a domestic animal and ^nd of large sue, a parasite 
be placed in that hetero»«« Africa, this trypanosome must 
g eous collection whose type is T. brucii 
