1910.] PAUASITIC IMJOTOZOA OK KED GItOL'SE. f595 



Gametocytes. 



Tiio growing parasites gx-;\flua]ly become round, and two forms 

 can be distinguished to some extent in life (contrast figs. 20 

 and 22) and more easily niter carefid staining (tigs. 4 and 8 

 from figs. 5-7). In one tlie protoplasm is relatively hyaline 

 (figs. 4, 8, 9, 11, lo, 14); in the other foi-m it is granular 

 more deeply staining and may be slightly alveolar (figs. 5, 7, 

 10, 12, 15, 16). By analogy with the malarial parasite, tliese 

 rounded Leucocyto/.oa are considered to be gametocytes, the 

 slightly smaller, hyaline pai^asites (figs. 11, 13, 14) being charac- 

 terised as males, while the slightly larger, broader and moi-e 

 granular Leucocytozoa (figs. 1(*, 12, 15, 16) are designated females. 

 The females or maci'ogametocytes, which measure 14 yu.-20 ^ by 

 1 0/1-1 6 ^<, appear to be souiewhat more numerous than the males 

 or microgametocytes, which are about 13 /^-17 f.L by 6 ju-12 /u. 

 The nuclei of the gametocytes are not well marked, even after 

 long staining. The nucleus of the microgametocytes (figs. 4, 9. 13) 

 is often somewhat larger than that of the macrogametocyte 

 (figs. 6, 10, 12), is ill-defined (figs. 11, 13, 14) in contour, and 

 frequently has small granules of chromatin scattered within it 

 (figs. 11, 14). The macrogametocyte has a better defined nucleus 

 (figs. 6, 10, 12), in which a larger granule of chromatin— a karyo- 

 some — is sometimes present (figs. 5, 6, 10). Small chroma.toid 

 granules are often seen at eithei' pole of the gametocytes (fig. 4, 1 1 , 

 1 3), sometimes more numerous at the ends of the microgametocytes 

 (figs. 4, 9, 11, 13) thau at the ends of the macrogametocytes (figs. 10, 

 12). These chromatoid granules are, I think, more probably 

 deriv'atives of the nucleus of the host-cell in process of absorption 

 by the paiusite than actual chi-omidia within the parasite, for 

 sometimes the chromatoid granules aie clearly outside the parasite 

 (figs. 6, 7). _ 



The details of the maturation of the female gametocyte to 

 form the macrogamete are little known — probably the macro- 

 gametocyte becomes the macrogamete with little or no cytological 

 change. Danilewsky (1890), and Sakharoft* (1893-5) desei^ibed 

 the formation of flagella-like microgametes from the hyaline 

 microgametocyte mfresli pi'epai-ations of the blood of certain owls, 

 crows, and rooks. The microgametes (males) of L. zieinanni 

 were considered by Sciiaudinn (1904) to be formed normally in 

 the mid-gut of a mosrpiito which sucks the blood of tlie avian host 

 (an owl). The more recent observers of avian Leucocytozoa have 

 not usually seen gamete formation in the fresh state, so far a.s 

 can be gathered from their published accounts. 



Matins a,nd Leger (1909) have recently made the very in- 

 tei-esting statement that thei'e is a periodicity in the occurrence 

 of the gametocytes of L. caulleyri in the blood of the fowls they 

 in vestigated at Tonkin. The events of the life-cycle of the parasites 

 in the period intervening between their appearances in the blood 

 aie unknown. There seem to me to be several alternatives possible : 



