254 



for the most solid contribution to our knowledge of the 

 Ligules.* 



Writing in 1876, M. Duchamp observes: "During the 

 last seven or eight years a veritable plague has over- 

 whelmed the fish in the ponds of La Bresse, afflicting ex- 

 clusively the Cyprins and especially the tench, whose 

 deaths may be reckoned by hundreds of thousands. From 

 such a total it will be readily understood, without com- 

 mentary, what serious losses the country has sustained. 

 It was soon discovered," he says, " that the author of the 

 disaster was a tapeworm lodged in the peritoneal cavity of 

 the fish outside the intestine. Since then, the white worm 

 of the tench, for so they call it, has been well known to 

 salesmen in our markets, but no one thought of troubling 

 himself about its zoological history." 



From what follows in the text of M. Duchamp's work 

 we gather that until the time in question no notice had 

 been taken, or at least not recorded, of the existence of 

 these parasites. " If they had been encountered, the num- 

 bers were so restricted that the fact was passed unnoticed." 

 All at once these parasites appeared in such abundance 

 that they caused terrible ravages amongst the occupants of 

 the ponds, and severe losses to commerce. "Two years 

 ago," adds M. Duchamp (i.e., in 1874), "the malady seemed 

 to be on the decrease ; to-day, however (1876), the ligules 

 are so common that we have had no difficulty in procuring 

 them ; and, unfortunately, in our country they have not yet 

 arrived at the degree of rarity attributed to them by hel- 

 minthologists. Whatever may have been their frequency 

 they have remained quartered in the ponds that are encoun- 



* ' Recherches sur les Ligules,' par G. Duchamp, M.D., &c. Paris, 

 1876. 



