50 POPULAR SCIENCE MONTHLY. 



Fish Poisoxixg. — Some fisli are supplied with poisonous glands, 

 by means of which thej secure their prey and protect themselves 

 from their enemies. The " dragon weaver," or " sea weaver " 

 (Trachinus draco), is one of the best known of these iish. There 

 are numerous varieties widely distributed in salt waters. The poi- 

 sonous spine is attached partly to the maxilla and partly to the gill 

 cover at its base. This spine is connected with a poisonous gland; 

 the spine itself is grooved and covered with a thin membrane, which 

 converts the grooves into canals. When the point enters another 

 animal its membrane is stripped back and the poison enters the 

 wound. ]\Ien sometimes wound their feet with the barbs of this 

 fish while bathing. It also occasionally happens that a fisherman 

 pricks his fingers with one of these barbs. The most poisonous 

 variety of this fish known is found in the Mediterranean Sea. 

 Wounds produced by these animals sometimes cause death. In 

 Synanceia hrachio there are in the dorsal fin thirteen barbs, each 

 connected with two poison reservoirs. The secretion from these 

 glands is clear, bluish in color, and acid in reaction, and when in- 

 troduced beneath the skin causes local gangrene and, if in sufiicient 

 quantity, general paralysis. In Plotosus lineatus there is a pow^er- 

 f ul barb in front of the ventral fin, and the poison is not discharged 

 unless the end of the barb is broken. The most poisonous variety 

 of this fish is found only in tropical waters. In Scorpcena scrofa 

 and other species of this family there are poison glands connected 

 with the barbs in the dorsal and in some varieties in the caudal fin. 



A disease known as hakke was a few years ago quite prevalent 

 in Japan and other countries along the eastern coast of Asia. 

 With the opening up of Japan to the civilized world the study of 

 this disease by scientific methods was undertaken by the observant 

 and intelligent natives who acquired their medical training in Eu- 

 rope and America. In Tokio the disease generally appears in 

 May, reaches its greatest prevalence in August, and gradually dis- 

 appears in September and October. The researches of Miura and 

 others have fairly well demonstrated that this disease is due to the 

 eating of fish belonging to the family of Scomhridce. There are 

 other kinds of fish in Japanese waters that undoubtedly are poison- 

 ous. This is true of the teirodon, of which, according to Remey, 

 there are twelve species whose ovaries are poisonous. Dogs fed 

 upon these organs soon suffered from salivation, vomiting, and 

 convulsive muscular contractions. When some of the fluid ob- 

 tained by rubbing the ovaries in a mortar was injected subcutane- 

 ously in dogs the symptoms were much more severe, and death 

 resulted. Tahara states that he has isolated from the roe of the 

 tetrodon two poisons, one of which is a crystalline base, while the 



