390 The Philippine Journal of Science 1920 
bedded among which were found engorged capillaries. In 
one of the vessels I found numerous amoebae collected within 
the lumen of the capillary in which were also found leucocytes, 
red blood corpuscles, and remnants of the shed endothelial lining 
of the vessels. This finding of the amoebae inside the capillaries 
indicates the way the amoebae spread through the tissues, that 
is, by the vascular system. 
The question now arises as to whether this amoeba is a new 
one. It is evident from the description given above that it can- 
not by any means be classed as Entamoeba histolytica. As no 
other amoeba has been proved to be pathogenic, the one under 
consideration is then a new pathogenic species. It is necessary, 
however, to compare the structure of this amoeba with other 
species that have been found in human faeces by other observers. 
I need not refer, in this connection, to the large number of 
ill-defined species of amoeba described by writers who did not 
use modern staining methods. The only types to which this 
amoeba has resemblance are Vahlkampfia ( Amoeba ) Umax and 
Entamoeba nana. Vahlkampfia Umax found in human faeces 
as described by Wenyon(6) is a very small organism that does 
not measure more than 10 ^ in diameter. Furthermore, the 
nucleus is situated centrally and is spherical. There is no dif- 
ferentiation between the ectoplasm and the endoplasm so far 
as can be seen. It then becomes necessary to compare this 
species with Entamoeba nana, for this variety has been found 
recently to be very common throughout the world. It has been 
reported from Egypt, England, the United States, (3) the Phil- 
ippine Islands, and other places. Most of those who have re- 
ported on it are agreed that it is nonpathogenic. From the 
description of the species as given by Kofoid, Kornhauser, and 
Swezy(4) we find that the nucleus has a massive karyosome that 
is situated on one side of the nuclear membrane, the remainder 
of the nucleus being empty. Entamoeba nana, as described by 
Dobell and Jepps, (2) has a fragmented karyosome. These de- 
scriptions differ from the nuclear structure of the amoeba under 
consideration. Furthermore, the characteristic distinction be- 
tween the ectoplasm and endoplasm, which is a very prominent 
character in my amoeba, has not been found in the other two 
amoebae. Moreover, these being nonpathogenic, they cannot be 
the same species as this one. 
As no cyst has been found by me, it is not possible for 
me to compare these amoebae with respect to their encysted 
forms. 
