STUDY OF PATHOGENIC AMtEB/E FROM BOMBAY. 119 
placed on fresh agar medium. A single amoeba twelve hours 
later was found to have escaped from the cyst and was 
moving over the medium. Forty-eig’ht hours later a single 
amoeba was alone still actively moving over the culture 
medium ; no multiplication had occurred. On the third day 
the amoeba had become encysted again. In this case a 
single amoeba had emerged from a single cyst and moved 
about for two days on the culture medium, which was free 
from any bacterial growth; no multiplication had taken place, 
but on the third day encystation had again occurred. 
(2) A few cysts free from bacteria were planted out on an 
agar medium which, in the first place, had been smeared on one 
occasion with fresh sterile mouse's liver, on another occasion 
with fresh sterile unheated guinea-pig’s liver. The amoebae 
in due course emerged from their cysts and were observed to 
feed upon the red blood-cells and broken-up liver-cells of the 
smeared agar surface. The liver-cells which were not 
damaged or broken were too large to be engulfed by the 
amoebae, which were approximately of the same size as these 
cells, some amoebae, however, made attempts to swallow whole 
liver-cells, spreading themselves around the cells m a thin 
layer, but never succeeding in completely surrounding the 
liver-cell. A single amoeba on one occasion was watched for 
two hours and a half while moving about on the agar medium 
smeared with fresh sterile guinea-pig’s liver. During this 
time this amoeba ingested and digested four red blood-cells, 
and attempted as well to take up a number of liver-cells as 
large as itself. 
While thus the large amoeba of the liver-abscess culture 
was seen to feed upon red blood-cells and broken down liver- 
cells, very little multiplication of the amoebae was noted. 
Generally, without dividing, the amoeba) became encysted 
again. This was inferred from the fact that the number of 
cysts found after some days was very little in excess of the 
number originally placed on the medium. With the object 
of stimulating multiplication of the amoeba) the following 
procedure was adopted : 
