180 
H. M. WOODCOCK. 
central ami liavlng- the conspiciioiis, deeply staining body in 
close association with it (figs. 20-20). On the other hand 
parasites of the second type, with the nnclens near one end 
of the body, occur nearly always in corpuscles in which the 
alteration is far advanced, the cytoplasm being, at the best, 
only with difficulty discernible and the nnclens greatly 
elongated and narrowed (figs. 32-40). As is only to be 
expected, however, occasional exceptions to the above regular 
conditions are to be met with. Thus, an individual may 
be found, having its nuclear arrangement of the first type, 
which has already caused considerable elongation and 
alteration of the host-cell nucleus (figs. 8, 28, 29) ; conversely, 
a parasite may have acquired the second type of nuclear con- 
dition before the corpuscle-nucleus has become very elongated 
and narrow (figs. 10, 31). It may be regarded as practic.-illy 
certain, therefore, that the second type of individual is a 
rather later or older phase in the development of the first 
typo of parasite. In addition to the evidence afforded by the 
various stages in the alteration of the infected corpuscles, 
this conclusion is .also supported by the following points. 
Parasites of the second type are on the whole distinctly lai-ger, 
that is to say, they have more bulk than those belonging to 
the first category ; further, the only individuals seen free 
(fig. 21), or which have manifestly only recently entered a 
corpuscle (figs. 19, 26), have the first type of nuclear 
arrangement.^ 
It is not difficult, I think, from a careful comparison of 
different individuals, to form a fairly acciu-ate idea of the 
manner in which the change in nuclear position and character 
is brought about ; and for this purpose it is necessary to study 
the behaviour, in relation to the nucleus, of the characteristic 
deep-staining body which is associated with the latter in the 
young forms of the Haemogregarine. In the earliest phase 
this body, which from now onwards I will designate according 
' I have never oltserved any individuals of the Larger, older type free — 
that is to say, which could have been liljerated from a corjjuscle, 
whether with or without the enveloping capsule. 
