268 
The Life History of Amoebae 
common Umax type showing a dark staining karyosome surrounded 
by a clear halo, the latter being sometimes enclosed by a nuclear 
membrane (figs. 1-2). Besides amoebae showing irregular outlines 
(due to their being fixed when moving about), rounded forms are 
observed (fig. 4) probably representing initial stages of encystment. 
Similar forms, measuring 5-6 p,, are seen surrounded by a distinct 
cyst wall (figs. 5-6). The karyosome of these cysts produces small 
chromatic granules (fig. 5) which are found afterwards in the cyto¬ 
plasm. The next stage shows division of the nucleus (fig. 7), the cyst 
now containing two nuclei and some (commonly two) small chromatic 
particles. Sometimes the nuclei are dissolved into many chromatic 
granules (fig. 9) but this is not a common occurrence and is probably 
to be considered as a sign of degeneration. Stages similar to these 
represented by figs. 5-6 are described by James, who, however, did 
not find binucleate cysts. Although most of the cultural Umax show 
only uninucleate cysts, binucleate cysts are also described as e.g. by 
Nagler (1909) in Amoeba diploidea and consequently it is probable 
that the amoeba found in this case, was a common Umax form, tem¬ 
porarily developing in the human intestine. We want to emphasize 
however that in this case the stools were always examined, immediately 
after deposition; consequently errors resulting from examination of stools 
where amoebae had time to develop outside the host, are to be excluded. 
The second case referred to is that of a Javanese surgeon for the 
time residing in Holland. There are some records of dysentery in early 
youth but no definite information was to be obtained and neither 
Entamoeba histolytica, nor E. coli or dysentery bacilli were to be found. 
The patient complained of intermittent pains in the bowels accompanied 
by fluid or semi-fluid stools containing some mucus. In the stools 
of normal consistency no parasites were to be seen, but in the semi¬ 
fluid stools were found Blastocystis hominis and Umax (amoebae and 
cysts). The case was observed regularly from March 25th till July 16th. 
The following table shows the results: 
March 25th. 4-nucleate cysts. 
April 2nd. 2- and 4-nucleated cysts, amoeba. 
April 8th. Id. more amoebae. 
April 9th. After ingestion of 25 grammes MgSOj cysts and 
many amoebae; after the stools have become quite fluid 
only amoebae. 
Weekly inspection till July 16th. Amoebae and cysts when stools 
were fluid. 
