MEGALOPS THRISSA. 1 23 



eruption or efflorescence on the skin, violent pain in the stomach, 

 tenesmus, great acceleration of pulse, cold sweats, insensibility, 

 convulsions, and death. In some cases, where the fish does not 

 prove immediately fatal, the whole surface of the body acquires a 

 deep yellow hue, as in jaundice, and the urine is likewise highly 

 tinged of the same colour. 



The cause of this deleterious quality in fish is still involved m 

 considerable obscurity. By some the poisonous principle has been 

 ascribed to copper, with which the fish becomes impregnated from 

 the copper bottoms of ships. It has, however, been remarked that 

 copper does not cause the symptoms described above, and on che- 

 mical examination no traces of copper can be detected in any part 

 of the poisonous fish. Dr. Burrows, the author of a very excellent 

 paper on this subject in the London Medical Repository, vol. iii. 

 p. 445, is inclined to think that the poisonous quality of fish is not 

 confined to any particular part of the animal. He observes that 

 it does not exist in the skin, or to the stomach and intestinal 

 canal, or in the liver and gall-bladder exclusively, although there 

 is no doubt that persons have been poisoned from eating these 

 various parts. It pervades the whole fish ; and this is abundantly 

 proved by the statements of Dr. Chisholm, and the numerous 

 authors adduced by him. The theory which ascribes the effects 

 of poisonous fishes on the human system to changes induced 

 by the substances on which they feed (the Medusae and Holo- 

 thurise) is well known to be unfounded. Many facts have 

 been adduced by Kcempfer, Clarke, Forster, Thomas, Chisholm, 

 and others, to show that the Yellow -bill Sprat, Barracuda, 

 and other poisonous fishes, when eaten fresh or having no 

 marks of disease, were perfectly harmless, and that the same fish, 

 whether fresh or salted, on the following day was highly poisonous. 

 Hence Dr. Burrows concludes that the poisonous quality is occa- 

 sioned by some morbid change in the system of the fish, and that 

 this quality is a poison sui generis, always more active after the vital 



powers cease. 



With respect to the treatment of poisoning with fish, the primary 

 object is to remove the noxious matter from the stomach. This 

 is to be accomplished by emetics, administered in the usual way, 

 or by the use of the stomach-pump. The best emetic is the sul- 



