298 
Entamoeba histolytica and E. ranarum 
the few tadpoles obtained were therefore mixed together into a single 
culture (C). After hatching, the tadpoles were allowed to remain un¬ 
disturbed for a few days, during which time they fed upon the remains 
of the jelly from the eggs. The remains of this were then removed, 
the dirty water replaced by clean filtered water, and the cultures then 
subdivided for the experiments. 
Culture A was divided into three parts—subcultures A 2 and A 3 , 
with the remains of the original culture kept as a control (Aj). Culture 
B was similarly divided into five subcultures, B 2 , B 3 , B 4 , B 5 , and the 
original as control {Bj). Culture C, containing very few tadpoles, was 
divided into two—subculture C 2 , and control (C j). I thus had seven 
subcultures for feeding experiments, and three control cultures contain¬ 
ing tadpoles derived from the same parents and bred in exactly the 
same way. 
The attempts to infect the tadpoles by feeding them upon cysts of 
E. histolytica were all made in the same way, and may therefore all be 
described together. A quantity of human faeces—varying in amount in 
different cases—which contained large numbers of cysts of E. histolytica, 
was placed in a glass tube. This was then put into the dish containing 
the tadpoles to be experimented upon, and allowed to remain. I had 
but little doubt that the tadpoles would eat the faeces, and at the same 
time the cysts, without any further inducement; for in nature they 
eat the excrement of other animals, and decaying organic matter of all 
sorts. My expectations were more than realized. The tadpoles greedily 
devoured the human faeces as soon as it was offered to them. Indeed, 
they seemed greatly to prefer it to any other food with which I attempted 
to feed them; and the tadpoles so reared, in spite of the filthy condition 
of the water in which they lived, were very healthy. They grew rapidly, 
and in two cultures attained a larger size than those in the controls. 
Not only did they eat the original human faeces with avidity, but 
they continued to ingest and reingest it many times after it had passed 
through their bodies. I several times observed a gorged tadpole still 
gorging itself upon human faeces, whilst another simultaneously de¬ 
voured the long coil of faeces protruding from its anus. There was 
never any doubt, therefore, that the tadpoles would have abundant 
opportunities of infecting themselves, if this were possible, with any 
cysts or organisms present in the original human faeces. 
The seven different experimentally fed subcultures were fed upon 
faeces from seven different convalescent carriers of Entamoeba histolytica. 
In every case I examined the faeces carefully before giving it to the 
