160 
E. A. M1NCHIN AND H. M. WOODCOCK. 
This was the only occasion on which we were able to see 
the fertilisation of a female gamete of Leucocy tozoon, but 
several times we observed the male gametocyte in' the act of 
flagellating, i.e. of developing the microgametes. This 
process occurred more readily in coverslip preparations to 
which a drop of salt-citrate solution had been added than 
in those put up of pure blood alone. When the micro- 
garnetocyte ruptured its host-cell its body protoplasm was 
usually more or less segmented or divided up into two or 
three lobes or portions from which the male elements were 
given off, just as was described and figured by Schaudinn 
(loc. cit.). The number of microgametes formed appears 
to be variable. Schaudinn gives the number as eight ; on 
the other hand, Laveran (7) figures four as arising, also in 
this species of Le ucocy tozoon {“ Haemamoeba ” zie- 
manni). In one case we saw three quite distinctly, and 
there may have been a fourth, but we could not be certain ; 
in another instance, where the body of the parasite (freed 
from the host-cell) had been constricted into two masses, 
only one male element was seen to be formed. It is not 
improbable that in the citrated drop some gametocytes 
may be stimulated into attempting to develop microgametes 
before they are really quite mature enough to do so in a 
completely normal manner. Thus in the last instance given, 
the solitary microgamete, at first flagellum-like and active, 
appeared unable to liberate itself from the protoplasmic mass, 
and after five or six minutes its wrigglings became less active 
and more spasmodic, and finally it became much contracted 
and pear-shaped and ceased to move. In other cases, again, 
the microgametocy te did not succeed in rupturing the 
enclosing envelope of the host-cell, and the microgametes 
were developed inside the skin or capsule, as it were, of the 
leucocyte, from which they were unable to get free. In one 
instance several male elements (there may have been as many 
as eight) were seen thus imprisoned ; they were in two 
bunches, directed towards the spindle-like ends of the host- 
cell, and were lashing themselves about vigorously in the 
