The Source of Bothriocephalus latus in Japan, 



Isao Ijima, Ph.D. 



Bothriocephalns latus, which was formerly thought to he 

 restricted to Europe .in its distribution, is the commonest tape-worm 

 found in Japan. It is met with everywhere in the country, of course 

 with local differences as to its frequency. The identity of the species 

 with the European f )rm admits in my o})inion of no doubt, I would 

 not have made this remark, had not Küchenmeister of late errone- 

 ously assumed that in Europe more than one species is included under 

 the name of B. latus. 



As far as my experiences go. Taenia mediocanellata occurs in 

 Japan much more rarely than B. latus ; among dozens of tape- worms 

 that I have examined, only a single specimen of the former species 

 M'as found. That fish, the recognized source of Bothriocephalus, 

 is used as food much more generally in Japan than beef (the source 

 of Tœnia mediocanellata), sufficiently explains the above-stated fact. 

 Tcenia solium, if ever it occurs in Japan, must be exceedingly rare. 

 I have indeed, never as yet met with it in Tokyo. This is un- 

 doubtedly due to the fact that pork as an article of food is even less 

 used than beef. Unfortunately means are not yet at my disposal for 

 determining the occurrence of human tape-worms at any locality on 

 statistical grounds. 



