Gr. H. F. Nuttall and G. S. Graham-Smith 259 
found in all blood-platelets, yet it is by no means rare. And when it 
does occur there is not such marked distinction between the nuclear 
masses as one sees in trypanosomes, but still as much distinction as 
many of Kinoshita’s drawings would indicate for Babesia ....Thus it 
would be an easy matter to mistake such blood-platelets for real 
flagellates having true nuclear dimorphism.” “ The flagella and 
pseudopodia stain like cytoplasm, and not like chromatin as in the 
trypanosomes.” 
Swingle concludes his paper with the following words : “ It is not 
sufficient answer to the similarity I have shown to say that Kleine 
used defibrinated blood, and hence blood-platelets were not present in 
his solutions, for no one has demonstrated that the platelets are entirely 
removed by defibrination. Since blood-platelets in various culture 
media and in the stomach of the tick always develop flagella, move 
about, and manifest such a marked resemblance in form, size, and 
structure to Babesia and the Leishman-Donovan bodies, investigators 
must furnish criteria to differentiate between the flagellated platelets 
and the parasites. Until they have established their position by 
experiments with normal blood, the correctness of their results can 
be accepted only with some reserve. The evidence I have presented 
shows that neither are motion and flagellation exclusive characters of 
parasites nor will they differentiate them from blood-platelets. Each 
student will have to determine experimentally how to distinguish the 
two classes of structures.” 
As controls for our observations we have carried out a number of 
experiments by Swingle’s method, using defibrinated blood from normal 
and infected dogs. Occasionally we have found platelets such as he 
has described, but the majority of cultures showed none. We do not 
think that the intracorpuscular forms of piroplasma with radiating 
processes could be mistaken for platelets, and up to the present we 
have not met with any “ flagellated ” platelets which could be mistaken 
for the extracorpuscular parasites. 
DESCRIPTION OF PLATE XIX. 
Fig. 1. Large free pyriform parasite with two chromatin masses. 
2, 3, 4. Large intracorpuscular parasites each with several chromatin masses. 
5, 6. Large intracorpuscular parasites with short radii. 
7. Small intracorpuscular parasite with several radii. 
8, 9. Intracorpuscular parasites with long radii. 
10-16. Intracorpuscular parasites with numerous radii, some of which apparently 
penetrate the corpuscular envelope. 
