Adults and Ova 115 



capense, to distiuguisli it i'L-om the Egyptian parasite which gave rise to 

 both types of eggs. The subject remained one of merely academic interest 

 until 1902, when Sir Patrick Mauson saw in London a case of intestinal 

 bilbarziosis, contracted in the West Indies, in which lateral-spined eggs 

 only were present. In the following year he put forward the suggestion 

 that : "Possibly there are two species of Bilharzia, one with lateral-spined 

 ova, depositing its eggs in the rectum only, the other haunting bladder or 

 rectum indifferently " [328] . This view was revitalized by Sambon in a 

 series of papers, commencing with one in 1907, in which he formally 

 named the new species after Sir Patrick Manson, " in appreciation of this, 

 one of his many genial intuitions" [425, 426, 427, 428]. Sambon's new 

 species met with an unsympathetic reception, more especially from Looss, 

 who held, with many elaborate arguments, and with some apparent success, 

 that vesical and intestinal lesions in bilharzial infections in Egypt were 

 caused solely by the one species, B. hcematohia. The whole controversy 

 cannot be reviewed here, but the curious reader will find in the prolonged 

 debate "a stimulating vituperativeness " which makes it highly entertain- 

 ing, if somewhat cruel reading. 



In his "Eemarks on Schistosomum mansoni," Sambon 



„ [-^'25] explained that his "determination is based principally 



on the characters of the eggs," but that, in addition, he had 

 " taken into consideration their different geographical distribution, the 

 different anatomical habitat, and the different pathogeny of the two 

 species." He maintained that " the lateral-spined ova are not found 

 occasionally only, within the distributional areas of >S'. licBinatohium, as 

 would necessarily be the case if they were the product of this species, but 

 have a peculiar and wide geographical distribution of their own, being 

 absent in many places where endemic h£ematuria and its causative agent 

 are prevalent (Cyprus, South Africa)." 



-J- , The opposing theory put forward by Looss was, briefly, 



rp that " unfertilized females are not capable of producing 



other than abnormal eggs." These abnormal eggs were 

 for the most part the lateral-spined variety, and where they contained a 

 miracidium this was attributed to parthenogenesis. Looss' position, which 

 met with clever criticism from Sambon, became somewhat changed later in 

 the light of his own further observations, but his main tenets remained, 

 and his final ground became, theoretically, unassailable without the aid of 

 experimental evidence. 



J , In Looss' opinion " the strange and striking differences 



Arguments pr'esented by the clinical and pathological pictures of 



bilbarziosis as seen in various places " could be explained 



" on the presumptive life history of the parasite, in connexion with the 



habits of the host and the conditions of the country " [295] . 



Commencing with his postulate that infection is direct and takes place 

 at all times through the skin, he maintained that the miracidia proceed to the 



