16,6 Haughwout et ah: Protozoal Dysentery 645 
radical in the metabolism of the drug should be carried well in 
mind. 
I have noted, in connection with several cases of intestinal 
entamoebiasis treated with benzyl benzoate, that the patients 
apparently did not pass cysts as convalescence progressed. This 
has seemed worthy of note in passing, but I have seen the same 
thing occasionally when other drugs have been employed; and 
it not infrequently happens that persons infected with Entamoe- 
ba histolytica fail to discharge cysts, in sufficient numbers to 
admit of their detection in the fseces by the methods usually 
employed, for periods of weeks or even months. Unfortunately, 
we have been unable to keep track of our discharged amoebic 
cases, so we cannot tell if they are still infected. However, 
only one of these has applied to us for treatment of a relapse, 
and he had previously left the hospital notwithstanding his 
faeces still contained motile Entamoeba histolytica and we had 
warned him that he was far from cured. 
To settle the question as to whether or not this patient was 
absolutely sterilized as regards his Balantidium infection it 
would, theoretically at least, seem necessary to make serial sec- 
tions of the entire colon. However, this is obviously imprac- 
tical, even had we fixed and embedded the entire organ. It 
has only been possible to minimize the chances of missing the 
organisms by dividing the tissue into many small blocks and 
taking sections from each block. This we have done and, so 
far, we have been unsuccessful in our search for the organisms. 
We offer the evidence that we have collected with the promise 
to continue our studies and report in greater detail in the near 
future. 
The clinical phenomena observed in this case were, in gen- 
eral, similar to those we have seen in our entamoebic cases. 
While we have had opportunity so far to treat only two cases “ 
of balantidiosis, I am inclined to believe that we shall find benzyl 
benzoate to be as efficacious in balantidial as it seems to be in 
entamoebic infections. 
It is again seen that the drug exerts no influence on helmin- 
thal infections. 
The death of the patient was clearly due to causes unrelated 
to the balantidial infection. 
’ As this paper is being written I am studying a case, somewhat similar 
to the foregoing, with Dr. Wenceslao Vitug, in the Philippine General 
Hospital. 
