288 
ON THE OCCURRENCE OF HYDATID CYSTS 
IN MONKEYS. 
By WILLIAM NICOLL, M.A., D.Sc., M.D., D.P.H. (London). 
{From the Lister Institute of Preventive Medicine.) 
In 1909, Professor McIntosh of St Andrews University sent me a 
cyst from the abdominal cavity of a South African baboon, Cynocephalus 
porcarius Budd. The cyst, which was single, had been ruptured in 
removal, part of its contents had escaped, and some blood had entered 
it. The cyst measured about 20 mm. in diameter, was a typical 
hydatid, and resembled in its general structure the ordinary simple 
unilocular hydatid of man. 
Attached to the cyst wall and scattered throughout the grumous 
contents were numerous scolices. These were ovo-globular in outline 
and measured on an average 0-215 x 0-175 mm. The head or body of 
the scolex measured 0-095 x 0-12 mm. while the tail measured 0-12 
x 0-055 mm. The four suckers measured approximately 0-054 mm. 
in diameter but the size varied from 0-042 mm. to 0-063 mm. 
The head was surmounted by a double row of hooks, rather straight 
in type, and measuring 0-021-0-027 mm. in length. The average 
number of hooks was 38. 
As is well known the hydatid tapeworm which passes its adult 
stage in carnivores, particularly dogs, is one of the most widely dis¬ 
tributed parasitic worms known. It occurs in greatest profusion in 
countries and districts where dogs or other Canidae are numerous and 
especially where there are many cattle and sheep. Few parasites, 
however, possess such an extensive and varied list of intermediate 
hosts and the number of species of animals known to function as 
such probably exceeds forty. 
Man, unfortunately, is by no means an uncommon intermediate 
host and is only too frequently fatally affected. Short of death the 
parasite gives rise to many symptoms of the most serious nature, the 
only remedy for which in most cases is operative treatment. 
