430 



Mr. Karop said that, as on former occasions, when Mr. Rosseter 

 had placed his most interesting work on the structure and Hfe- 

 history of these avian tape -worms before the Club, the invitation 

 to discuss the paper produced no response. The fact was that 

 this subject was one taken up by very few in this country, and 

 it was also one which required a large amount of patient, and, 

 to many people, repulsive investigation ; and he had often wondered 

 at, and admired as well, Mr. Rosseter's indefatigable industry in 

 working as he did under, to say the least, unfavourable conditions. 

 A microscopist, however, was supposed to take the whole world 

 for his province, and although he himself had very little experi- 

 ence practically of tape- worms, he was once a pupil of Dr. Cobbold, 

 and moreover had to know for teaching purposes the very extra- 

 ordinary life-history of the species infesting man and the domestic 

 animals he used as food. Mr. Karop then gave a brief account of 

 the metamorphoses of Tcenia saginaia and T. solium, as some aid 

 to those members who, otherwise unacquainted with those entozoa, 

 might wish to follow Mr. Rosseter's elaborate and valuable morpho- 

 logical paper. 



Mr. Hilton asked if Mr. Rosseter could give them any infor- 

 mation as to the manner in which development was accelerated 

 or retarded, say by temperature or any other causes. 



Mr. Rosseter said that temperature had nothing whatever to 

 do with the matter. In the particular species he had been 

 describing the segments were dropped into the water by the ducks, 

 and if the eggs were taken up by a crustacean they would 

 develop, but only up to a certain point ; but if after this they 

 were not met with by a suitable host, they died, but if taken up 

 by a duck they would become mature in its body. 



Mr. Karop asked if Mr. Rosseter knew whether the mortality 

 amongst ducks in this country was much increased in consequence 

 of this particular tape- worm ? 



Mr. Rosseter said that nothing of this kind had been recorded 

 in this country, but there had been epidemics due to this cause 

 reported from the Continent. 



Mr. Karop, in reply to a question as to the conditions under 

 which these tape-worms would reach their mature stage, said 

 that unless there were two hosts it was impossible for them to 

 mature. The chances of these conditions occurring were rather 

 remote, and no doubt a very large number of the eggs never 



