38 Philippine Journal of Science 1920 
in the stools. Diagnosis of the other cases was made by means 
of the cysts. Considerable variation was noted in the size of 
the cysts in some of the cases, which suggests that there may 
be two or three local strains or races—possibly with varying 
degrees of virulence. Our figures of incidence are lower than 
those of Liverpool children as recorded by Matthews and 
Smith, (40) who found 16.4 per cent in children between 1 and 
5 years of age, and 14.3 per cent in children 5 to 12 years old. 
The case in which the Giardia trophozoites appeared in the 
stools was of some interest. It was presented by a boy 7 years 
old who had been suffering from a severe and protracted 
attack of ileocolitis. Previous to its onset he had vomited as- 
carids. The stool was examined for the first time on August 
21. It was soft and yellow, and beyond the preseiitce of the 
ova of Trichuris nothing especially noteworthy was seen. Con- 
centration of this stool showed a heavy infestation with Trichuris 
and nothing more. The same observations were made when the 
stool was again examined on August 23. 
On August 26, however, the stool was diarrhceal, and large 
numbers of Giardia trophozoites and cysts were present. Some- 
thing apparently had happened to the flagellated forms for they 
were practically nonmotile, and those that showed any signs 
of life were sluggish and moved about as if they were water- 
logged. “Blastocysts” were found in considerable numbers; 
also Entamoeba coli, some of which had engulfed small “blasto- 
cysts.” The following day both the trophozoites and cysts of 
Giardia were absent from the stool and they did not appear 
again during the time the child was under observation. This 
child was heavily parasitized with both protozoa and helminths; 
and it is, of course, impossible to fasten the blame for persistent 
abdominal pain, before the onset of the dysentery, on any par- 
ticular one of them. We are inclined to believe that the pain, 
which was complicated at times by distention and tympanism, 
was stirred up by the Trichuris infection. 
Case 84, a boy 10 years of age, gave a history that might be 
referred to Giardia. The child came into the hospital suffer- 
ing from tetanus and an infected wound of the right foot. He 
received antitetanus serum and recovered. The stools were 
markedly diarrheal and contained Spirochxta eurygyrata and 
cysts of Giardia. The patient gave a history of occasional ab- 
dominal pain but had never passed or vomited worms. No 
helminth ova were found. The general physical and mental 
