Fish-poisons.[157]—Very little accurate knowledge is extant regarding these. Many fish are poisonous, and among them are the synanceia, found in the Indian Ocean between the Netherland Isles and New Caledonia; considerable numbers are found in the neighborhood of the latter locality. These fish are provided with spiny rays which are in direct communication with a poisonous system having its seat in the dorsal fin. The prick of one of the spiny rays of this fish may under certain circumstances result fatally, and in every case it causes a rapid and painful gangrene.
From the reservoir the poison is conducted to the sharp extremity of the spines by a deep channel with which each spiny ray is provided; the animal has 26 poison-sacs, two for each ray, and the sacs burst when the corresponding sting is in any manner compressed.
The poison is an odorless liquid having a slight styptic or acidulous taste, and exhibiting a bluish fluorescence; it rapidly becomes turbid.
The weevers, which are numerous on the shores of the Mediterranean Sea, and which are also met with in the northeastern portion of the Atlantic Ocean, are likewise very dangerous, which explains their popular names "viper-weever," "spiderweever," etc. These fish are provided with a double set of poisonous apparatus, the one opercular, which is the more dangerous, and the other dorsal. The opercular spine has a double channel in connection with a conical cavity hollowed out in the base of the opercular bone. The bottom of this cavity is provided with special cells which secrete the poison. The dorsal glands have a similar structure.
The poison of the weever is a liquid, limpid when the fish is alive, and turbid when dead; it has a slight bluish fluorescence, is neutral in reaction, and is coagulated by acids and bases. It acts as a paralyzant, its action being exerted on the medulla and spinal cord; it retards the heart's action.
These examples will suffice; and we will not dilate further on this subject, because, as already stated, but little is accurately known regarding the subject, and what is known may be summed up as follows: Fish-poisons always give rise to an intense pain, frequently with motor paralysis, followed by paralysis of sensation; they affect the heart, arresting it in diastole; and they are more dangerous to fish and cold-blooded animals than to mammifers.
Poisons of the Hymenoptera.[158]—The poison system of the bee, and of such insects as the wasps, bumblebees, etc., is known to consist of a hollow sting consisting of two sharp needles communicating with two poison-bearing glands, and forming a flexible tube. One of these glands secretes an acid liquid (formic acid); the other secretes an alkaline fluid.
The action of the bee-poison is very often benign, but there have been cases where death followed the infliction of numerous stings.
Our information regarding the poison of the cantharides and flies is very vague[159]; the same is true of the poisons of various arachnids, acarides, and myriapoda. So far as spiders are concerned, it is known that their poison is an oily liquid having an acid and bitter taste, and containing a toxalbumin derived from the skin of the insect. The bite of the ordinary spider occasions simply a slight local pain, with redness; that of the large poisonous spider, however, may kill the larger animals, and even man.
Poison of Scorpions.[160]—This poison is a colorless, acid liquid, having a higher specific gravity than water, in which liquid it is soluble. The famed legend of the suicide of scorpions is well known to all. It is stated that when the insect finds itself in a position where its death is inevitable, it stings itself, and dies from the effects of its own poison. A simple method has even been described of bringing this result about experimentally by surrounding the insect with a circle of fire. Bounne, of Madras,[161] who has studied the procedure, has demonstrated its entire falsity by showing, first of all, that the insect dies from the effects of the excessive heat, and further, that the poison of the scorpion is harmless to individuals of the species that furnish it.