136 Heport of tJie Bilharzia Mission in Egypt, 1915 



Lymngeus, as Katsurada announced in a footnote to an article on " Schisto- 

 somiasis japonica," in December (C.f. Bkt., 72, p. 378). Miyairi's original 

 publication is in Japanese, but Kumagawa gave a summary of the chief 

 points in an abstract published in the Tropical Diseases Bulletin,' in 

 March, 1914. 



" They noticed also that in the infested locality there are many snails 

 in the waterways and ditches. Of these snails a great many Cercarise 

 parasitize one which has a dark-coloured shell with seven spirals. The 

 authors carefully picked up a number of young non-infected snails and 

 tried whether the miracidia entered their bodies or not. They found 

 that the miracidium enters the body of the snail, penetrating the cuticle 

 with the lips and proceeds to the gills and the wall of the digestive canal. 

 After twelve days the first redise appear and gradually concentrate to the 

 hepatic ducts, elongating, and a number of the second redise are seen. 

 The authors put mice into the vessel in which the full-grown snails were 

 fed, for three hours every day and repeated this experiment for four days. 

 After three weeks they found a great many Schistosoma japonicum in the 

 livers of the mice. The authors conclude that this kind of snail is an 

 intermediate host of S. japoniciun." 



Judging by titles, other papers appeared in Japanese journals, but these 

 are inaccessible. During 1914, Katsurada (according to an Italian abstract) 

 " confirms the assertion of Miyairi and Sudzuki, but regards the question 

 of the intermediate host of S. japonicum as not altogether cleared up." 



It is evident that the above information, while definitely establishing 

 a molluscan intermediary for B. japonica, was of little value as a guide to 

 the elucidation of the special problems surrounding the B. hcematobia 

 transmission, and gave no facts regarding the bionomics of the infective 

 stage, or of the carrier, upon which to base prophylactic measures. In 

 Egypt all attempts to advance by infecting with the miracidia had failed, 

 even in Looss' skilled hands. Sonsino and others had found no means of 

 identifying the B. cercaricB among the numerous developmental stages 

 found in the snails of the endemic area in Egypt. There was not available 

 for experimental purposes any animal of known susceptibility but man. 

 Lastlj', there still remained no explanation of the frequency of bilharziosis 

 amongst very young children in Cairo. 



In an article published in Mense's Handbuch in 1914, Looss admitted 

 when dealing with B. japonica, that after Miyagawa's experiments the 

 existence in this species of a free swimming cercaria was quite plausible. 

 Under B. hcEmatohia, however, he states that if it is correct that there is 

 an intermediate host in the Oriental species, " then B. japonica must 

 differ essentially in its development from B. hcematohia." That Looss' 

 view was still maintained by others is shown by the advice tendered to the 



' Full titles and abstracts of the preceding and of all available publications on 

 B. japonica are to be found in the volumes of the Tropical Diseases Bulletin, 



