Gr. H. F. Nuttall and C. Strickland 
73 
(B) The stained parasites. 
Having studied the living parasite, we were in a better position 
than previous observers to understand the significance of the forms 
which are encountered in stained films. Certain forms, however, still 
require investigation. Reference to the protocols relating to the horses 
upon which we experimented (see Appendix, N. equi Horses I-III, 
pp. 85-89 and charts) shows the results of the examination of their 
blood diaring the course of the disease induced by this parasite. 
The parasites stain in a similar manner to Piroplasnia. The 
hyaline cytoplasm takes on a blue colour with Giemsa’s stain and the 
nuclear structures are stained deep carmine. The blue staining cyto¬ 
plasm may appear more or less vacuolated or condensed peripherally. 
Definite nuclear changes precede the division of the cytoplasm ; these 
changes are considered on p. 75 (Diagram VII) and p. 84 in the 
description of Plate III. 
'Time when the qxirasites appear in the blood. Percentage 
of infected corpuscles. 
Ho7'se 1. The parasites appeared in the blood on the morning of 
the eighth day after inoculation, roundly 0'6 "/o of the corpuscles being 
found infected in the afternoon. They gradually increased in numbers 
up to the afternoon of the tenth day, when 5'4 "/o of the corpuscles were 
infected ; and on the eleventh day, when the horse died, they had 
decreased slightly in numbers. 
Horse II. The parasites appeared on the seventh day after 
inoculation. They gradually increased in numbers so that roundly 1 “/o 
of the corpuscles were found infected on the tenth and eleventh days. 
Their number then fell rapidly so that only isolated parasites could 
be detected up to and including the 21st day, after which they 
disappeared and the horse recovered. 
Horse III. The parasites appeared on the tenth day after 
inoculation, 0'2Yo of the corpuscles being found infected. They 
increased in numbers up to the twelfth day, when 11'6 “/o of the 
corpuscles contained them. They persisted in fair but somewhat 
variable numbers (5 to 13 “/o of the corpuscles being infected) from 
the 13th to the 20th day, when the horse died. 
The number of infected corpuscles enumerated in these horses 
attained at most 5’4 7o, 0‘9 "/o and 13’2“/o, respectively. The parasites 
