42 
Blood Parasites 
Piroplasma divergens in Cow. 
I found these piroplasrns in three cases of Redwater Fever in cows 
locally. The parasite is more generally known as Piroplasma higeminum 
or P. bovis, but as Prof. Niittall pointed out to me the species met with 
in England is P. divergens. 
The number of red corpuscles containing parasites varies enormousl}^ 
in one case only about 2 “/o were infected, whilst in another 23 “/o of the 
corpuscles contained one or more parasites. 
In one case the piroplasrns were associated with the presence of the 
large trypanosome which I have previously described. 
The infected corpuscle most commonly contained a single round 
parasite which is usually situated towards the mai'giu. Double pear- 
shaped parasites were fairly numerous but in no case did I meet with 
two double piriform parasites in one corpuscle. A comparatively small 
percentage showed the method of multiplication described by Nuttall 
(1908) in which “the peculiar piriform parasites develop through 
a process resembling budding from a large, rounded, or slightly amoeboid 
parasite, the whole of whose protoplasm flows into the ‘buds’ and 
gives rise as a rule to two piriform parasites without a residual body 
being left” (Nuttall). Free piriform parasites were extremely 
infrequent. 
The Halteridia of Birds. 
Halteridia were found in numerous birds, especially the thrush, 
blackbird, starling, finch, jay, etc. Generally the infection was slight 
but in very young birds, particularly the thrush and blackbird, 
parasites were exceedingly numerous. They were nearly always found 
in association with other parasites, e.g. leucocytozoa, filaria or rarely 
trypanosomes. All stages were seen and some excellent permanent 
preparations were obtained of flagellating bodies and ookinetes. 
(Plate III, figs. 24, 25, 26, 28 and 29.) 
I was struck with the diversity of appearance of halteridia met 
witli in the same and in different species of birds. They showed 
differences in their size, shape, nature of the protoplasm, nucleus, and in 
the quantity and distribution of the melanin pigment, and these factors 
were apparently independent of the age and sex of the parasite or the 
method of staining adopted. 
Durirm an examination of the blood of birds extending over more 
O O 
than fifteen years I have never met with the slightest indications of the 
transformation of the halteridium into a trypanosome. 
