Metchinkoff[162] has confirmed these facts, and has moreover demonstrated that the blood of the scorpion possesses an undoubted antitoxic power against the poison of the insect.
The poison of the scorpion serves it to kill the insects which are its prey. Frogs and birds stung by the scorpion also generally die. A dose of 0.0005 Gm. kills a guinea-pig in less than one hour; and according to Calmette[163] less than 0.0005 will kill a white mouse in two hours. Oxidizers destroy the toxicity of the poison. Guinea-pigs immunized against the poison of the scorpion resist perfectly very large doses of the poison.
Poisonous Blood and Serums.—It is an almost general fact that the blood and blood serum of batrachians, eels, lampreys, snakes (even non-poisonous ones), and hedgehogs are very poisonous. Mosso has found in the blood serum of the lamprey a toxin possessing a strong hemolytic power, and which he has named ichthyotoxin. O.5 Cc. of this serum injected into a dog kills it in a few minutes. He also observed, in 1888, that the blood of the eel, in like dose, kills a dog almost immediately, and that the blood contains an ichthyotoxin analogous to that of the lamprey.
This substance, which appears to be closely allied to the sero-albumin of the blood, has a phosphorus-like, sharp, and burning taste. By digestion it loses its toxicity, as well as by heating at 68° to 70° C. It is easily obtained by precipitating with ammonium sulphate the serum of eels, and dialyzing the precipitate dissolved in water. The power of this substance is almost as great as that of the cobra poison, 0.002 Gm. being instantly fatal per kilo of dog.
The blood of snakes is likewise very toxic; the same is true of the blood of the viper, as 0.02 Cc. will kill a guinea-pig in two hours. All these bloods lose their toxicity when heated above 70° C. The serum of the hedgehog is peculiar in this respect; when heated at 38° C. for fifteen minutes it loses its toxicity, but it then possesses an immunizing power against the poisons.
The subject possesses great interest, because it was in studying these immunizing properties that Camus and Gley,[164] and later on Kossel[165] and Tchistowitch,[166] discovered the first anticytotoxin,[167] which they obtained by treating the animals with increasing quantities of the serum of eels. On mixing the antitoxic serum of these animals in vitro with the red blood-corpuscles of the species furnishing the serum and of the hemolytic serum of eels, it is found that the blood-corpuscles kept quite well.
As to the blood of the hedgehog, we have already seen that Physalix and Bertrand have shown that it may be a counter-poison towards serpent-venom under certain conditions. In its normal condition it is highly toxic.
Poisonous Meats.—It is particularly among the fish that we find these normally present, and it is a singular fact that, for a given species, the toxicity frequently depends upon the period of the year. Thus, at the period of spawning, certain fish may be extremely poisonous, or, on the contrary, may entirely cease to be so. The anchovy ballassa from the shores of India occasions death even in very small quantity; the poisonous meltite of the same seas causes violent vomiting; the fugu of the Japanese seas possesses an extreme poisonousness at the spawning period, while, on the contrary, it is perfectly innocuous at all other periods.
Numerous cases of poisoning have been chronicled every year by the journals, due to the ingestion of mussels; in the flesh of these crustaceæ is found a dangerous toxin, methylotoxin. The flesh of oysters is also unwholesome at the spawning period.
The toxic symptoms caused by these animals become apparent in not less than twenty-four hours after ingestion. The poisoning due to these fresh meats must not, however, be confounded with that caused by tainted or spoiled meats.