88 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
ani and Besta, 1936) : Vegetative and precystic forms of E. histolytica 
were found in 33 percent of the cockroaches examined 24 to 48 hours 
after they had fed on bread inoculated with this organism. A few 
cystic forms were found in one of the cockroaches after 10 days. 
Periplaneta americana, Gold Coast Colony (Macfie, 1922). Cock- 
roaches used in this experiment were carefully examined for amoe- 
bic invasions because some of these insects at Accra had been found 
naturally invaded (whether by E. histolytica, E. coli, or both is not 
clear). Cysts of E. histolytica were found in the feces of seven of 
nine cockroaches fed human feces containing cysts of this organism. 
The cysts appeared to be unharmed by passage through the insects; 
they were seen in the feces for only 1 to 3 days. U.S.A. (Frye and 
Meleney, 1936): The cockroaches were fed on a culture of cysts 
mixed with rice flour and sugar. Cysts were first found in the feces 
16 to 20 hours after the cysts had been eaten. Development of this 
protozoan was obtained from cysts collected in cockroach feces after 
48 hours. 
Cockroaches, Venezuela (Tejera, 1926): Nymphal cockroaches 
were fed feces containing numerous cysts and mobile forms of £. 
histolytica. After 24 hours, the feces of 6 of 20 cockroaches contained 
cysts. After 48 hours, the feces of 8 of another 20 cockroaches con- 
tained cysts. Three days later, 6 cockroaches of another group pro- 
duced cysts. The cysts were verified as dysenteric amoebae by feeding 
contaminated cockroach feces to three kittens. A few days latter, the 
kittens showed unmistakable signs of dysentery and typical dysenteric 
amoebae were found in their feces. 
Class CILIATA 
Order SPIROTRICHA 
Family BURSARIIDAE 
Balantidium coli (Malmsten) 
Disease.—Dysentery and diarrhea in man and monkeys. 
Experimental vectors——Cockroaches, Venezuela (Tejera, 1926): 
30 cockroaches were fed hog feces containing many B. colt cysts. 
After 24 hours, 4 of 10 cockroaches passed cysts in their feces. After 
48 hours, the feces of 8 of 10 cockroaches contained cysts. Typical 
B. coli cysts were found in the intestines of the remaining 10 insects. 
A monkey (Cebus capucinus) was infected with B. coli by eating 
cockroach intestinal contents that contained cysts. Dysentery devel- 
oped with attendant diarrhea. Numerous B. coli were recovered from 
the contents of the monkey’s colon. 
