When the naval officer blew on his ice cream to cool it, the medics raised their eyebrows but did not laugh. Nor did they think he was wacky; he was just getting over a kind of fish poisoning which the medical profession calls ichthyotoxism. It is the only disorder doctors know of in which temperature reactions are reversed, e.g., a victim complains that his hot soup is cold, or that his ice water is scalding his tongue.
Why this is, nobody knows. Nor does anybody know why a victim thinks his teeth are loose when they are not. In fact, there are plenty of mysteries about ichthyotoxism, and the chief of them is that doctors do not really know what causes ichthyotoxism. It is not to be confused with poisoning caused by the bite of a venomous fish, however, or by eating stale fish in which bacteria have been at work. It comes from eating fresh, healthy fish, of species that have been used as food for generations, e.g., the amberjack that poisoned the naval officer.
In the Tropics. One notable case occurred on Saipan in 1949, when 55 Filipinos sat down to a feast of eel. Before the night was out, two were dead, one had to have his larynx slit to save him from choking to death, and the rest had suffered from a variety of symptoms ranging from vomiting, diarrhea and cramps to the staggers, paralysis and convulsions. Last February in Hawaii, there were 24 similar cases, all traced to fish imported from Palmyra Island. So far, there have been few clear-cut cases reported from the temperate zone; nearly all have been from the tropics.
Last week a research physician named Bruce W. Halstead was hard at work at the College of Medical Evangelists in Loma Linda, Calif, sorting out a mass of puzzling data and trying to find answers. In his laboratory, four assistants were slicing little samples from the flesh, liver, intestines and gonads of a batch of frozen fish from Johnston Island. After grinding and centrifuging, a cubic centimeter of fluid from each sample was injected into the belly of a mouse. If the sample was weakly poisonous, the mouse got sick but lived; a moderately poisonous sample should kill it within 36 hours, and a strongly poisonous sample within an hour.
Across the Reef. Dr. Halstead has learned to take nothing for granted. Once he was testing two puffers, identical except that one came from Hawaii and the other from the Phoenix Islands. The Hawaiian fish was harmless. It seemed pointless to test the other, but he did so anyway: the mouse died in convulsions in 4½ minutes. In this case the fish came from waters 2,000 miles apart, but Halstead has found that fish taken on one side of a reef may be safe, while those on the other side, a mile away, are deadly.
Some fish live by eating marine plants and others live by eating other fish. Both kinds can cause the mysterious poisoning. Dr. Halstead's hypothesis: the poison comes from plants, with the fish-eating fish picking it up from the plant eaters. The poison itself is probably an alkaloid, but Dr. Halstead has not been able to identify it. Next month, Dr. Halstead will head for Okinawa and Japan to get fresh material for his study: the western Pacific is full of it.