114 
Hciemoflagellates, etc. 
forms found in the peripheral blood, but have probably developed from 
balteridia. It is quite a well-known fact that small trypanosomes may 
be frequently found in the bone marrow of birds, and we think it most 
probable that these small forms may develop into the larger ones Wood¬ 
cock figures. Woodcock believes that the great difference in the 
number of trypanosomes, as compared with the balteridia, is largely 
reduced when the sexual forms of the intracellular parasites are omitted. 
As a result of his observations, Woodcock concludes that “Halteridium 
is probably a stage in the life history of a trypanosome which has 
advanced a step further and become adapted also to the red blood 
corpuscles.” It should be noted that Woodcock’s results appear to be 
based on the study of stained films of the peripheral blood, heart blood 
and organs of a single chaffinch. We are not told whether the parasites 
were studied in the fresh condition, or whether more than one bird was 
examined. We are left in doubt also as to what the halteridium of 
the chaffinch might do in the stomach of its transmitting invertebrate; 
Woodcock’s observations are based on such a small amount of material, 
that it is really difficult to ascertain what part of the life cycle of the 
parasite he was dealing with. 
As far as we are aware, no other observers have noted this so- 
called nuclear dimorphism in balteridia in the blood of birds. We have 
examined many specimens of the male and female elements of the 
halteridium of Athene bi'Cima from the blood of the owl, but we must 
admit we have never seen a true blepharoplast in any of them. It is by 
no means proved that the structure Woodcock describes as a kineto- 
nucleus is a true blepharoplast; as far as we can gather, this view is 
chiefly based on its staining reactions. 
We are unable to accept Woodcock’s explanation of the difficulty in 
finding so few examples of the intermediate stages, between the halteri¬ 
dium and the small trypanosomes. Surely, if this parasite is to become 
a trypanosome, and provided a sufficient number of birds are examiued, 
there ought to be no difficulty in finding numerous examples of all the 
stages in this very important change. The single parasite, which Wood¬ 
cock depicts as illustrating one of the changes towards the formation of 
a trypanosome, may represent anything, as it is lying free in the plasma. 
We can find no proof that it is destined to become a trypanosome. We 
therefore think it is extremely doubtful whether the trypanosome of the 
chaffinch has any connection with its halteridium; Woodcock’s observa¬ 
tions certainly do not support any such conclusion. We would like to 
see a more exhaustive study of fresh preparations of a large number of 
