Certain poisonous fishes have developed spines for stinging or laceration, and in connection with these stings have developed glands secreting poisons. These are comparable to the fangs and poison glands of venomous snakes, and like them function as protective devices. Probably, also, these glands, like those of the snakes, have by a perversion of metabolism been developed out of what would normally have been perfectly harmless organs. Such fishes poison men only when they sting them. Comparable is the poisoning which comes from the injection of the blood serum of a fish into the blood stream of a mammal and, by inference, of a man. As indicated above this is an experimental operation, and does not concern us here.
Finally there is the fish poisoning by ingestion of the muscular or other tissues of the fish, the Ciguatera of the West Indies. Here we have undoubtedly two forms of poisoning—that by ptomaines formed in the partially decomposed tissues of the fish, and that by toxins secreted in various organs but particularly in the ovaries and less notably in the testes at the breeding season. In the literature, as in ordinary medical practice, the two kinds of poisoning are almost hopelessly entangled.
From what has been said, it is clear that in the disease called Ciguatera there is an interesting, and, so far as the West Indies are concerned, an almost virgin field for investigations by modern clinical and chemical procedure for the differentiation of these two kinds of poisoning and for putting the treatment on a sound scientific basis.
The only region where any biochemical study of these toxins has been made is in Japan. In this great fish-eating country poisonous fishes of the family Tetrodontidae abound in harbors and bays having on them fisheries stations and universities with trained men and with laboratory facilities at hand for making such highly technical studies. In the whole of the West Indies there is but one such laboratory known to me. In Havana, Cuba, whose harbor abounds in fishes accused of causing Ciguatera, is the Laboratorio Finlay. Dr. W. H. Hoffmann, one of the workers in this, has interested himself in this disease and, on the basis of the data he has collected, has published two short papers. A series of such studies is necessary clearly to differentiate the two forms of poisoning from eating tropical fishes—that caused by ptomaines (products of bacterial decomposition), and that caused by the secretion of toxins (presumably toxalbumins) in the tissues, especially of the reproductive organs, at certain seasons of the year.