496 POISONS : THEIR EFFECTS AND DETECTION. [§ 649. 
III.—Poisonous Fish. 
§ 649. A large number of fish possess poisonous properties ; in some 
cases the poison is local, in others the poison is in all parts of the body. 
The Murcena helena has a sort of pouch connected with four strong 
conical erectile teeth or fangs, not dissimilar to the poison apparatus 
of a snake ; its bite is said to cause toxic symptoms in man. 
Many fish are provided with poison glands in connection with the 
fins or special weapons, and such are used for purposes of defence. For 
example, Synanceia brachio is provided with a back fin consisting of 13 
spines, each of which has two poison reservoirs ; the reservoirs are 
connected with 10 to 12 tubular glands which secrete the poison, a 
clear, feebly acid, bluish fluid, exciting in a concentrated condition local 
gangrene ; the constitutional effects, according to Pohl ( Prayer med. 
Wochenschrift, 1893), in frogs experimentally injected with the poison, 
are mainly referable to the action of the poison on the heart, which it 
directly paralyses. Bottard has recorded five fatal cases in man. 
The Fugu-Poison of Japan. —The Japanese chemists have given the 
name of Fugu-poison to that which is found in the ovaries of various 
species of Tetrodon , a common fish in Japanese waters. Although con¬ 
centrated in the ovaries, small quantities of the poison have been found 
in the liver and the blood. The various species known of Tetrodon are, 
with the exception of Tetrodon cutaneus , all poisonous, but in unequal 
degrees. The most poisonous are Tetrodon chrysops, pardalis, ver- 
micularis, and poecilonotus ; while less poisonous are Tetrodon rubripes, 
porphyreus, stictonotus, and rivulatus ; it is believed that the same 
poison exists in all the fishes named. D. Takahashi and G. Inoko, 1 in 
1890, began a chemical research upon the poison of the Tetrodon genus ; 
and G. Tahara, in 1894, separated two principles, the one crystalline, the 
other amorphous—Tetrodonin and Tetrodonic acid. The fresh roe of 
the fish, after being mashed, is submitted to dialysis ; the dialysate 
is purified by lead acetate, and then precipitated by alcohol; a 
crystalline mass results, being a mixture of tetrodonin and tetrodonic 
acid. The latter is separated by dissolving in water and converting it 
bv means of silver acetate into a silver salt ; the tetrodonin is then 
«/ 
precipitated by alcohol. 
Tetrodonin is crystalline, neutral in reaction, soluble in water ; the 
aqueous solution not precipitable by the usual group alkaloidal reagents. 
It is insoluble in ether, benzene, and carbon disulphide ; it is with 
difficulty soluble in alcohol ; 50 mgrms. of this substance injected into 
a dog weighing 1-9 kilogrm. killed it in half an hour. 
Tetrodonic acid is amorphous and hygroscopic ; 10 mgrms. per kilo, 
apparently kills dogs in about thirty minutes. 
1 Zeitschrift d. med. Ges. in Tokio, viii. 
