N. H. SWELLENGREBEL AND R. M. M. WiNOTO 269 
Observations of fresh tnaterial. The amoebae move very slowly 
and die quickly under the cover-glass. This can be demonstrated 
by examining them in eosin solution. The amoebae are then seen as 
white patches on a red background, vacuoles being indistinct, the 
nucleus invisible. When the amoeba dies, the cytoplasm becomes less 
refringent and is faintly stained by the eosin; the nucleus is stained 
more deeply, clearly showing the surrounding halo. Often the nucleus 
IV V VI 
Fig. 1. A Umax amoeba from case No. 2, drawn at intervals when moving. 
is expelled from the amoeba when dying. The amoebae found in the 
fluid faeces after purgation with sulphate of magnesia are more actively 
motile. The pseudopodia are stumpy, ordinarily one at a time is 
extruded (c/. Text-fig. 1). No contractile vacuole was observed. Since 
the amoebae are easily killed when outside the human body it would 
seem that they are real parasites (cultural Umax remains alive for a 
much longer time under similar conditions). Moreover after the use 
of a strong purgative, the amoebae found (they came from some part 
