Fig. 4.—Death-cup; destroying angel (Amanita phalloides Fries); reduced; natural size: cap, 31/2 inches; stem, 71/2 inches. (After Marshall, The Mushroom Book, by courtesy of Doubleday, Page & Company.)
The character of the poison was first carefully investigated by Kobert, who showed that the Amanita extract has the power of laking or dissolving out the coloring matter from red blood corpuscles. This hemolytic action is so powerful that it is exerted upon the red cells of ox blood even in a dilution of 1:125,000. Ford[26] has since shown that in addition to the hemolytic substance another substance much more toxic is present in this species of Amanita and he concludes that the poisonous effect of the fungus is primarily due to the latter ("Amanita toxin"). The juice of the cooked Amanita is devoid of hemolytic power, but is poisonous for animals in small doses, a fact that agrees with the observation that these mushrooms, after cooking, remain intensely poisonous for man. Extensive fatty degeneration in liver, kidney, and heart muscle is produced by the true Amanita toxin. In the Baltimore cases studied by Clark, Marshall, and Rowntree[27] the kidney rather than the liver was the seat of the most interesting functional changes. These authors conclude that the nervous and mental symptoms, instead of being due to some peculiar "neurotoxin," are probably uremic in character. No successful method of treatment is known. An antibody for the hemolysin has been produced, but an antitoxin for the other poisonous substance seems to be formed in very small amount. Attempts to immunize small animals with Amanita toxin succeed only to a limited degree.[28]
POISONOUS ANIMALS
While the muscles or internal organs of many animals are not palatable on account of unpleasant flavor or toughness, there do not seem to be many instances in which normal animal tissues are poisonous when eaten. As pointed out elsewhere ([chapter vi]), the majority of outbreaks of meat and fish poisoning must be attributed to the presence of pathogenic bacteria or to poisons formed after the death of the animal. This has been found especially true of many of the outbreaks of poisoning ascribed to oysters and other shellfish; in most, if not all, cases the inculpated mollusks have been derived from water polluted with human wastes and are either infected or partially decomposed.
In some animals, however, notably certain fish, the living and healthy organs are definitely poisonous. The family of Tetrodontidae (puffers, balloon-fish, globe-fish) comprises a number of poisonous species, including the famous Japanese Fugu, which has many hundred deaths scored against it and has been often used to effect suicide. Poisonous varieties of fish seem more abundant in tropical waters than in temperate, but this is possibly because of the more general and indiscriminate use of fish as food in such localities as the Japanese and South Sea Islands. It is known that some cool-water fish are poisonous. The flesh of the Greenland shark possesses poisonous qualities for dogs and produces a kind of intoxication in these animals.[29]
Much uncertainty exists respecting the conditions under which the various forms of fish poisoning occur. One type is believed to be associated with the spawning season, and to be caused by a poison present in the reproductive tissues. The roe of the European barbel is said to cause frequent poisoning, not usually of a serious sort. The flesh or roe of the sturgeon, pike, and other fish is also stated to be poisonous during the spawning season. Some fish are said to be poisonous only when they have fed on certain marine plants.[30]
There is little definite knowledge about the poisons concerned. They are certainly not uniform in nature. The Fugu poison produces cholera-like symptoms, convulsions, and paralysis. It is not destroyed by boiling. The effect of the Greenland shark flesh on dogs is described as being "like alcohol." It is said that dogs fed with gradually increasing amounts of the poisonous shark's flesh become to some degree immune. Different symptoms are described in other fish poisoning cases.[31]