Adults and Ova 127 



demonstration of mucous membrane invasion ; more especially as it brings 



me into line with the conclusions of Day. This distinguished observer 



came to the conclusion from a close study of the conditions of infection in 



Egypt that the nasal and oral ablutions, carried out as a part of religious 



ceremony, played no small part in the repeated infections with bilharzia 



seen in the Egyptians, more especially of male sex. One of the most 



heavily infected sites in Marg was at the water's edge immediately in front 



of the local praying ground upstream of the village. 



^ ^ From the established facts regarding the njode of spread 



Extent OF KisK ^ e t i- -l ■ -^ i. r^ i. i. -, • ■ \i • 



™ and of infection it is evident that troops deriving their 



water supply for all purposes from the large public water- 

 works run no risk of infection, even though the washing places become 

 accidentally contaminated with urine containing bilharzia eggs. The risks 

 were among those stationed in small parties on the various bridges, roads 

 and canal crossings throughout the Delta and among the troops occupying 

 new camps on the freshwater canal, in the Fayum and elsewhere. Although 

 supplied with pure water for drinking purposes, this had often necessarily 

 to be supplemented by local supplies for general purposes. At one such 

 place it was pointed out to me that the daily ration of water could be 

 supplemented with ease " from a wee bit burn" which seemed to be of clear 

 good water. A brief examination showed however that there were many 

 BuUinus in this stream, which was simply an irrigation channel derived 

 from a main canal on which was a large native population a mile or 

 two inland. 



Asked on one occasion what I thought were the risks from uncontrolled 

 access to canals in the neighbourhood of camps during the summer I put 

 down a conservative estimate of ten per cent. It is therefore of interest, 

 and indicative of the value of the propaganda and prophylactic measures 

 afterwards undertaken, that in two squadrons stationed at one of these 

 camps during the summer of 1915 no less than twenty-seven, i.e., about 

 twelve per cent strength contracted bilharziosis. 



With the information at the disposal of the troops bilharziosis should 

 now be treated as one of those diseases for which the individual is mainly, 

 if not entirely, personally responsible. 



Morphological Diffeeences between the two Egyptian Species. 



After the publication of B. mansoni as a distinct species in 1911, 

 several American workers made a study of the anatomy of adult worms 

 collected in the West Indies, Panama and Brazil, in search for morpho- 

 logical characters by which the species with lateral-spined egg could be 

 distinguished from the terminal-spined form found in the Old World. 



Comparing their finds with the formal descriptions given by Looss and 

 others, they noted and briefly described the following peculiarities. 



Holcomb [233] found that the adults of B. mansoni had a brown colour 

 and a somewhat larger ventral sucker. Piraja da Silva [411] was struck by 



