SNAKE-BITES AND POISONOUS FISHES. 125 



Poisonous Fish, Diseases and Injuries attributable to them. 



The subject of poisoning by fish is one on which there is very little 

 •recent information of any reliable character. Many ill-effects in different 

 parts are frequently put down to the ingestion or even handling of them. It 

 may be stated, however, with certainty that these are more common in 

 tropical than in temperate regions, no doubt due to the much more rapid 

 decomposition of the fish in the presence of heat and moisture, and perhaps 

 to the fact that as all animal life is more abundant in warm climates, so 

 the increased competition in the struggle for existence has caused many 

 fish to have developed peculiar organs having protective and poisonous 

 qualities. The noxious characters, as far as man is concerned, may be 

 divided into — 



(1) Toxic effects produced by the poison contained in the fish itself when 

 fresh. 



(2) Toxic effects produced by the ingestion of fish undergoing putrefaction 

 •either before being swallowed, or under certain conditions after it has been 

 a longer or shorter period in the intestinal canal. 



(3) The introduction into the body of specific pathogenic micro-organisms 

 through the agency of the fish. 



(4) Cutaneous wounds produced by the special armament of certain fish. 



(5) Diseases or growths produced by parasites of which the fish is the 

 definite or temporary host. In the constant investigation of fish markets for 

 zoological purposes, particularly in the Indo-tropical and Chinese regions, I 

 have been much impressed by the large number of apparently dangerous- 

 looking fish that are habitually sold, and the advanced stages of decomposition 

 which some of them frequently present, yet they seem to be used for food by 

 the poorer classes habitually. 



There used to be an old rule in the Navy that scaled fish were wholesome 



and that fish without scales were not. This, however, is certainly not 



altogether correct, as many with large scales, as Sphyrcena, Pagellus, etc., are 



at times markedly poisonous ; others without scales, as the fresh-water 



Silurokls, are esteemed as excellent food. 



As a matter of fact, poisoning directly due to the consumption of fish is 

 very rare in the naval service, and also among well-to-do Europeans in 

 tropical regions. 



The toxic properties inherent in fish, as Dr. Gunther pointed out, may 

 depend on various conditions ; some are only poisonous at certain stages of 

 growth, others only at special seasons, as at the breeding time ; again, others 

 are apparently dangerous after they have been feeding on poisonous foods ; 

 thus most of those beautifully-coloured fish belonging to the families 

 Squamipinnes and Labridce, which frequent coral reefs and browse on the 

 polyps of the young growing madrepores, etc., are generally considered to 

 be dangerous ; nevertheless, if these be properly cleaned before cooking, most 

 may be taken with impunity. French medical officers have pointed out that 



