386 Parasitic Worms 
to all sanitarians who have to deal with the problem of Bilharzia prevention 
and eradication. 
In the nature of constructive administrative policy Leiper adds: “If a 
campaign against bilharziasis were commenced on the lines here proposed it 
is evident that the whole scheme should be under the charge of a medical 
zoologist who should be attached, not solely to the Public Health service as 
in Ancylostoma campaigns, but also to the Department of Irrigation. In this 
way, only, could the full and continuous effect of the present administrative 
control of the Nile water be brought to bear upon the Bilharzia-carrying 
molluscs so as to ensure their permanent eradication from lands now heavily 
infected and their exclusion from new areas about to be reclaimed.” 
Of practical local measures which might, with advantage, be adopted 
Leiper suggests that unfiltered water from potentially infected sources such 
as canals, ditches and birkets would be rendered safe (1) if stored beyond the 
survival period of the cercariae, i.e. for at least forty-eight hours; (2) if heated 
. to 50° C., a temperature at which the cercariae are immediately killed; (3) if 
previously treated with chemicals which are lethal to the cercariae, e.g. 
chlorinated lime, benzoic acid, etc. 
Other noteworthy and important contributions to our knowledge of 
Bilharziasis are those of Katsurada (1913),Looss andKartulis (1913),Miyagawa 
(1913), Miyairi and Suzuki (1914), Ogata (1914), Narabayashi (1914), Cawston 
(1918), Liston and Soparkar (1918), Lutz (1920), Bahr and Fairley (1920) and 
Cort (1921). Of these the last mentioned is of most interest. Cort has been 
able to supply in the case of Schistosoma japonicum, in a fairly complete form, 
a knowledge of the course pursued by the parasites from their entry into the 
body till they reach their ultimate habitat in the portal veins. After pene¬ 
trating the skin or mucous membrane the larvae are carried by the veins or 
lymphatic vessels to the heart, whence they are conveyed to the lungs. Thence 
there appear to be two alternative courses. The first is via the pulmonary 
veins back to the heart and thence to the hepatic-portal system. In the 
second and possibly the more frequent course the larvae penetrate the sub¬ 
stance of the lungs. Thence, via the posterior and anterior mediastina, they 
migrate to the peritoneal cavity where they bore their way into the liver and 
so reach the hepatic-portal venous system. It is evident that in this compli¬ 
cated migration pathological effects may be produced in the lungs, liver, etc., 
in addition to the more characteristic pelvic and urinary symptoms. 
Interesting serological work in relation to Bilharzia infection has been 
carried out by Fairley (1919) who has prepared a specific antigen from the 
liver of molluscs infected with Bilharzia cercariae. More recent work on the 
same subject has been published by Le Bas (1922). 
It is a matter of some significance that indigenous cases of Bilharziasis 
have recently been recorded in Europe (Southern Portugal) by Franca (1921) 
and others, the intermediate host there being a subspecies of Planorbis 
corneus. 
