110 
W. GLEN LISTON AND 0. H. MARTIN. 
that while the smaller type varied in diameter between 6 and 
8 fj., the larger types varied in diameter between 12 and 15 /x. 
To determine whether the amoebae which developed from 
these cysts remained true to type, a single cyst was isolated 
under a lower power of the microscope on the point of a 
brush or needle which had been dipped in gum, and the cyst 
was then transferred to fresh culture-medium. It was found 
that the amoebae always remained true to type, that is to 
say, large cysts were always formed by amoebae which had 
developed from a single large cyst, while small cysts were 
always the product of small cysts. Moreover, the amoebae 
from the large cysts were considerably larger than the 
amoebae from the smaller cysts. There thus appeared at first 
sight to be two species of amoebae present in the liver-abscess 
culture. This supposition was further substantiated by the 
fact that the other two types differed in respect to (a) their 
methods of multiplication ; (b) their behaviour in saline 
solution; and (c) in other minor points. These points of 
difference will now be discussed. 
V 
(a) Methods of Multiplication on Culture-medium. 
The large amoeba was observed to multiply by endogenous 
budding as well as by division into two individuals. On one 
occasion a living amoeba in a pure culture derived from large 
cysts was watched for some hours. During this period three 
or four buds were formed within the body of the amoeba and 
liberated from it. This method of multiplication was more 
easily followed in fixed and stained specimens. Budding 
was observed both in old and in young cultures. In one 
case, an amoeba, which from its size appeared only lately to 
have emerged from its cyst, already contained a bud almost 
as large as itself (PI. 17, fig. 21), while an older and larger 
amoeba showed as many as six buds in various stages of 
development (PI. 16, fig. 4). It will be observed that the 
method of budding here demonstrated (PI. 16, figs. 1-5, 
PI. 17, figs. 16-20) differs materially from that described 
