322 THE GROUSE IN HEALTH AND IN DISEASE 



Gametocytes were found to be rare in the peripheral blood, more numerous in 

 heart-blood, and were also seen in smears of the liver and sjjleen of infected Grouse. 



Schizogony in the avian Leucocytozoa has not been recorded before. However, 

 in my investigations of L. lovati, I have succeeded in finding schizonts of this 

 Schizo- Leucocytozoon in the spleen of two infected birds (PI. xlvii.. Figs. 23-28). 

 Kony. J gg^^^ living Leucocytozoa in the heart-blood of these birds, and 



immediately made fresh smears of the internal organs. In the spleen were found 

 rounded or ovoid bodies — the schizonts — with thin walls, coloured red with 

 Giemsa's stain. These schizonts contained many merozoites (Figs. 25, 26). The 

 capsules of the schizonts are probably formed, at least in part, by the remains of the 

 host-cell (Fig. 26). The protoplasm of the schizonts appeared to be slightly granular 

 (Fig. 26). Some of the schizonts already contained a few nuclei in process of 

 multiplication by amitotic binary fissions (Figs. 23, 24), while other schizonts 

 contained small vermicular merozoites (Figs. 25, 26) which ultimately escape fi'om 

 the mother cell (Fig. 26) and may be found free in spleen smears (Figs. 27, 28), 

 when their mode of origin and general appearance are clearly grasped. A small 

 amount of residual protoplasm is left behind in the thin membranous remains of 

 the schizont which has just shed its merozoites. The schizonts are from 11^ to 14/x 

 by 8/x to 11^, and the merozoites are about 7fx in length. 



The birds whose spleens contained schizonts of L. lovati were not infected with 

 any other Hseraoprotozoon. 



Preparations made from the bone-marrow of infected birds, in which schizogony 

 might also take place, did not exhibit developmental forms. 



The method whereby Leucocytozoon lovati is transferred from Grouse to Grouse 

 has not yet been shown with certainty. The vector or second host of L. lovati will 

 Method of probably be found in some blood-sucking insect, which ingests the 

 transfer, parasites from one Grouse and transfers them to the next bird from which 

 it obtains blood ; or perhaps there is a cycle of development of the parasite inside 

 the Arthropod vector. 



The Grouse-fly (Ornithomyia lagopodis) suggests itself as a likely carrier or 

 second host of Leucocytozoon lovati. During my investigations I have dissected 

 several hundreds of Grouse-flies. In the gut-contents of a very few of these flies 

 I found unicellular motile vermicules, which may have been stages in the life-cycle 

 of L. lovati or perhaps of Hcemoproteus mansoni. In the Grouse-flies dissected I 

 never found cysts, such as occur in the stomachs of mosquitoes which have fed 

 previously on blood infected with malarial parasites. 



