320 THE GROUSE IN HEALTH AND IN DISEASE 



The presence of leucocytozoa does not always cause the body of the host-cell 

 to become spindle-shaped. Mathis and Leger (1909) found that the host-cell of 

 Leucocytozoon caulleryi of the Tonkin fowl did not have its ends drawn out. They 

 also considered that the host-cell was probably a mononuclear leucocyte. 



Personally, I have seen the spindle or horn-like end of the host-cell of L. lovati 

 elongate during the movements of the parasite within it. Further, both ends 

 usually are elongate (PL XLVii., Figs. 19-22), in other cases one end only becomes 

 deformed (Fig. 18), while in a very few cases the cell contour has been largely un- 

 affected by the parasite (Fig. 1 7). When both ends of the host-cell are affected, it 

 not infrequently happens that the elongation of one end is greater than that of the 

 other (PI. XLVi., Figs. 4-6). The shape of the host-cell of different Leucocytozoa 

 may be merely a reflex of the motility of the parasite within. It is not wise, 

 therefore, to lay too great stress at present on the spindle-shape of the host-cells 

 in diagnosing the Leucocytozoa of birds. 



The parasite in its younger stages is vermiform and like a Hpemogregarine 

 (PI. XLVI., Figs. 1-3; PI. xlvii., Figs. 17-22), and is more refractile in life than 

 Morpho- the host-cell containing it. Young forms are by no means common, a 

 yilug feature L. lovati shares with L. cauUeryi where they have rarely been 

 iorms. gggjj^ rpi^g nuclcus of the host-cell is displaced to one side (PI. xlvi., 

 Figs. 1-5), and the parasite moves very slowly within the cell, slight wave-like 

 movements or pulsations passing from the middle of the parasite towards either 

 end. The parasite grows in length and breadth meanwhile (Figs. 4-8), and the 

 ends of the host-cell become gradually more and more drawn out (Figs. 4-9, 

 and PI. XLVii. 18-22). As mentioned above, sometimes one end of the containing 

 cell is more drawn out than tlie other (PL XLvi., Figs. 4-6). Free vermicules of 

 L. lovati have very rarely been seen in my preparations of peripheral blood. 



The growing parasites gradually become round, and two forms can be dis- 

 tinguished to some extent in life (contrast PL XLVii., Figs. 20 and 22), and more 

 Game- casily after careful staining (PL XLVi., Figs. 4 and 8 from Figs. 5-7). In 

 tocytes. ^jjg |.|jg protoplasm is relatively hyaline (Figs. 4, 8, 9, 11, 13, 14); in 

 the other form it is granular, more deeply staining, and may be slightly alveolar 

 (Figs. 5, 7, 10, 12, 15, 16). By analogy with the malarial parasite, these 

 rounded Leucocytozoa are considered to be gametocytes, the slightly smaller, 

 hyaline parasites (Figs. 11, 13, 14) being characterised as males, while the 

 slightly larger, broader, and more granular Leucocytozoa (Figs. 10, 12, 15, 16) 



