30 



the female in which the pigment is concentrated 

 into a ring or figure of 8. Observe that attached to 

 these spherical bodies small ring-like bodies occur, 

 one to two in number, about as big as a pin's 

 head. These are the so-called ' polar ' bodies. 

 They occur in the male and female, and, as seen 

 in stained specimens, consist of little circular 

 masses of chromatin. These changes occur in 

 the tropics very rapidly, so that the examination 

 must be commenced as rapidly as possible. 



On watching these spheres, the pigment in 

 some will be seen to be in active motion — this 

 probably indicates the internal changes prepara- 

 tory to extrusion of flagella. Suddenly one of 

 these spheres is perceived to be oscillating violently, 

 and in a moment three or four or more pale, long 

 processes are emitted. The red cells all around 

 are put in motion by their violence, and it may 

 be only after a time, when the activity has grown 

 less, that the flagella are actually seen. Nodosities 

 will be observed in the flagella, and occasionally 

 a speck of pigment at their extreme end. The 

 flagella, after a time, break off, but they have 

 only once, by MacCallum, been seen penetrating 

 the female gamete. 



Under certain unknown conditions the cres- 

 cents do not become spherical and eventually 

 flagellate, but remain as crescents. 



Breathing on the slide, adding a trace of 

 water, etc., have been recommended to produce 

 the change more certainly, but it is probable that 

 the real cause lies in the state of development of 

 the crescent for certain observations, e.g., those of 

 Major Buchanan, I. M.S., shew that there is a certain 

 time after the fever when a maximum number of 

 gametes flagellate. 



