PROPHYLAXIS 43 



ment as is the rule. Dogs, cats, and other animals are 

 frequently infected with Schistosomum japonicum. 



Prophylaxis. We know too little on the subject for any 

 rational attempts at prophylaxis. In countries where the 

 disease is endemic, micturition or defaecation into water 

 should be prevented as far as possible. It would be well 

 to avoid the use of water both for bathing and drinking 

 derived from any source frequented by natives. The 

 general opinion rather favours the view that infection is 

 acquired by man whilst bathing. This opinion is sup- 

 ported by the observation that in Cape Colony the girls are 

 rarely infected, whilst the boys are commonly so. They 

 use the same drinking water, but the boys only bathe in 

 the rivers. On the East Coast, where the women do the 

 washing, standing in the water or wet mud of the streams 

 and ponds, they are as often infected as the men. 



A question that has excited a good deal of interest is 

 whether or not two species of worms are included under 

 the description Schistosomum hcematobium. Bilharz ob- 

 served that in the faeces the spine on the egg-capsule 

 was often lateral instead of terminal. In the urine the 

 eggs passed all have terminal spines ; in the faeces, in 

 most cases, particularly when the eggs are distributed 

 throughout the faecal mass, the spines are lateral. In 

 some cases only eggs with lateral spines are passed, in 

 others both may be present. The eggs with the lateral 

 spine are not immature or undeveloped, as they contain 

 a living miracidium. Either form of egg may be found 

 in the adult female worm. 



The geographical distribution of the two does not quite 

 correspond even in Africa, whilst* in South America and 

 the West Indies the lateral-spined egg in the faeces is 

 moderately common, and it is not certain if the terminal- 

 spined egg occurs. Endemic haematuria from infection 

 with Schistosoma is unknown in the West Indies and 

 South America. 



The balance of evidence is in favour of the presumption 

 that there is a second species which passes eggs with a 



