726 ROBERT MCCARRISON. 
Their size varies from 14 u-20 pw, the latter being the almost 
constant diameter of the 8-nucleated forms. ‘The cyst-wall 
varies in thickness, and sometimes it is made out with diffi- 
culty: It encloses a yellow staining granular protoplasm, one 
or more nuclei, and a characteristic port-wine staining area 
when treated with iodine (text-figs. 1 to 4). ‘The nucleus is 
spherical, very clearly defined, and shows refractile granules 
on its surface and in its interior. A well-marked karyosome 
is usually present. The nucleus varies in size from 2-3 
in the 8-nucleated cysts to 6-8) in the single-nucleated 
Taxt-ETE. }. TEXT-FIG. 6. 
rT \ 
; Nd rs 
/ gs ¥ an, Nica 
7 ¥ \ 7, 
Ee 4 
/ * ‘ | ae / & 
\ \ \ f 
‘ } 1 , y 
: rab : &. - 
Na | 
—_ Se 6. 
Text-fig. 5—Amebha I. Encysted ameba. The nuclear 
division has resulted in the formation of five nuclei; compare 
text- fig. Wa 
Text-fig. 6—AmebalI. Ene ysted ameba, 8-nucleated stage, 
cyst- wall ill- defined ; a centrally placed remnant of the port- 
wine staining area is seen—a very uncommon appearance at 
this stage. 
form. The nuclei vary from one to eight in number, dependent 
on the phase of development of the cyst (text-figs. 1 to 7). 
The commonest phases met with are those where the cyst 
contains one, two, or eight nuclei. Cysts showing four nuclei 
are much less commonly found. The port-wine staining area 
is present in the majority of all cysts containing one to four 
nuclei (text-figs. 1 to 4). It is not, as a rule, present in the 
8-nucleated cyst; I have only met with it at this stage of 
development in one instance (text-fig.6). Itis oval, spherical, 
or kidney-shaped in form, and occupies about one half of the 
