42 
Bilharziasis 
After the cercaria adhered to a fixed object, such as the skin of its host, 
by means of the oral sucker, the tail is cast off from the body in the following 
manner. The mouth muscles are contracted, and this act is followed by a 
protrusion of the papillae of the oral sucker; simultaneously, waves of con¬ 
traction pass along the body and the ventral sucker also obtains a firm hold 
of its victim. 
Rapid vibratile side-to-side movements of the tail then take place, and the 
fork is opened and closed in a forceps-like manner. In a short space of time 
the tail parts from the body at its membranous junction and floats away. 
Artificial Infestation of Monkeys. 
During the present investigation, we have produced artificial schistoso¬ 
miasis in 24 monkeys. 
4 were infested with Scliistosomum haematobium. 
20 were infested with Schistosomum mansoni. 
In most cases the dual routes of infestation, i.e. via both the skin and upper 
alimentary tract, were employed, but in two, infestation was produced by 
infected drinking water, and in six others, by the skin route only. 
Marked pruritus was a prominent manifestation in these monkeys; they 
scratched their skin or lips on those portions which had come in contact with 
the infected water. Manv of the soldiers infected at Tel-el-Kebir gave such 
a history of itching while bathing, or immediately after leaving the water. 
Indeed some of them actually left off swimming on this account. In three of 
the monkeys, definite skin rashes were observed the day after exposure, on 
the areas exposed to the action of the infected water. The existence of a similar 
rash in S. japonicum has been noted by Miyagawa. 
Similar phenomena were observed at the village of el Marg on the arms 
and legs of the Arab boys who collected snails from that locality, after immer¬ 
sion in the water of the smaller canals during collection of specimens. In the 
most heavily infected zones the itchiness was so marked that sometimes the 
boys voluntarily left the water on that account. In these cases, even within 
as short a period as 20 minutes, whitish papular elevations, the size of a small 
pin’s head, appeared closely together over the skin of their extremities. This 
rash never persisted for more than 48 hours. Intense itchiness was present, 
and scratching sometimes led to reddening of the part due to extravasation 
of blood into the papules. Infested snails could always be demonstrated in 
large numbers in water that produced these symptoms. As a matter of fact, 
we were able to learn the position of several highly infected localities, by find¬ 
ing, from interrogating the Arab collectors, those places where they developed 
this pruritus during collecting. 
In infestations through the upper alimentary tract the cercariae attach 
themselves to the mucosa of the buccal cavity either of the pharynx or of the 
oesophagus. 
A solution of hydrochloric acid, 1 in 1000, was found to quickly kill the 
