A CESTODE PARASITE IN THE FLESH OF THE BUTTERFISH. 129 



numbers of the cysts, which would not be the case if infection came only from the 

 accidental swallowing of eggs which had escaped from the segment and become dis- 

 seminated through the water. The evidence thus becomes strong enough to fasten 

 upon the butterfish, with a high degree of probability, the reputation of habitually 

 seeking these cestode segments where they are most likely to be found, viz, in the 

 feces of the hammmerhead shark. 



ECONOMIC CONSIDERATIONS. 



It has been asked. What is the effect of the presence of tliis flesh parasite on 

 the value of the butterfish as a food fish ? 



So far as the writer's knowledge goes, no very satisfactory answer can yet be 

 made to this cjuestion. It will require observations extending over several years to 

 ascertain whether the large proportion of butterfish found to be infected in the sum- 

 mers of 1904, 1905, and 1906 is normal or exceptional. If the number of butterfish on 

 the coast remains fairly constant year after year and sharks are migratory, so that 

 while there are large numbers one season there are few another, tliis would undoubt- 

 edly have an effect on the degree of parasitism in the butterfish in successive years. 



It is not likely that the parasites themselves have any effect on the nutritive 

 value of the flesh in which they are encysted, neither could their presence be detected 

 by the palate. That they work some disadvantage to the vitality of the fish is 

 shown by the results given above of the experiments in comparative weights. I 

 am not aware that the eating of butterfish has been followed by any after effects 

 which may not be experienced from the eating of any fish. Neither has it been 

 shown that the presence of these cysts in the flesh is accompanied with toxic prod- 

 ucts of any kind. Of course there is no danger whatever that these cysts can give 

 rise to adult tapeworms in warm-blooded man, even if he were in the habit of eating 

 fish which were only partly cooked, or even uncooked. 



The principal objection which can be made against the use, as food, of fish in 

 which cestode cysts are probably present is the very natural one which is based on 

 the popular prejudice against measly meat of any kind. This prejudice is not 

 only natural but doubtless rests on deep-seated racial experience. A recent com- 

 munication from Mr. M. B. Swift furnishes a good illustration of this prejudice, 

 as well as a confirmation of the unblissful state of the knowing. 



At his boarding place, a short time ago, butterfish were served, and he, after 

 surreptitiously inspecting the fish and finding in them the familiar cysts in large 

 numbers, decided that he would not take fish that day; but he neglected to state 

 his reason until after his table companions had partaken freely of the fish. He 

 then generously imparted to them his knowledge and demonstrated his lecture by 

 showing to his attentive audience the real presence of the subject of his discourse. 

 The result was immediate, startling, and in two cases disastrous to the intended 

 destination of the breakfast. 



Again, since we have here a food fish which apparently is almost invariably 

 infested with tapeworm cysts in the flesh, and often in great numbers, it is natural 

 that inf[uiry shoidd be made for some remedy for this affliction under which a 

 particular part of creation is groaning. Just how far man's interference with the 



B. B. F. 1906—9 



