Linton. — C est ode Cysts in Fish 123 



but since the case is fundamentally different from that of 

 trichina in pork, or "measles" in beef, it seems to me to be 

 advisable to make an attempt to prevent the prejudice, which 

 as yet is confined to a few individuals, and based, in great 

 part at least, on misapprehension, from growing to such an 

 extent as to banish an excellent food fish from our markets. 



V. IN DEFENCE OF THE BUTTERFISH 



The butterfish is exceptional among our marine food 

 fishes in that a considerable number of them have a small 

 cestode encysted in the flesh. These cysts are small, one 

 millimeter or less in diameter, and occur near the vertebrae, 

 usually on the ventral side of the back-bone between the 

 haemel spines. Now and then a fish is found which may 

 have many hundreds, or, in exceptional cases, a few thous- 

 ands, of these cysts in the flesh. It is worthy of note in 

 passing, and will be alluded to in another connection, that 

 the act of removing the back-bone, which is sometimes done 

 in preparing fish for the table, removes practically all of the 

 cysts, even in the most highly parasitized cases. Now these 

 cysts represent the larval stage of a small cestode whose 

 adult stage is passed in the intestine of a limited number 

 of species of shark, notably the hammerhead. And just 

 here it must be confessed one finds himself face to face 

 with an unpleasant and somewhat delicate situation. 

 Cestodes are not only worms but tapeworms at that, and, 

 say what one may, these words call up unpleasant associa- 

 tions. When it is learned, therefore, that the mess of but- 

 terfish, which a customer is about to buy, stands a good 

 chance of having a greater or lesser number of larval tape- 

 worms in the flesh, there should be little wonder if the cus- 

 tomer, who is acquainted with this possibility, decides to 

 buy some other kind of fish. 



Possibly some one may say: Why not leave the case of 

 the butterfish where it is? The demands of science have 

 been met by recording the fact that a certain species of ces- 



