238 



VENOMOUS ANIMALS 



ScorpcBfia scropha. — -In this fish the poison apparatus is said to 

 exist not merely in the dorsal fin, but also in the operculum. 



In the dorsal fin, the first three rays, which project about one- 

 third of their length beyond the membrane of the fin, are grooved 

 posteriorly by three channels, which are converted into canals by 

 a fine membrane, and communicate with the poison gland. 



On the operculum there are three small spines, of which the 

 longest alone is connected with a poison gland. 



When handled incautiously, a poisoned wound may result from 

 one of these poison spines entering the skin. The action of the 

 poison has been studied by Pohl, Brunton, and Briot: Brunton 

 describes the effects of the poison as being exactly the same as 

 that of Trachinus draco, and Pohl thinks that the poison acts on 

 the heart in the same manner as he describes for Trachinus. 



Fig. 29. — Cottus scorpms Linn^us. 



(From Savtschenko's ' Atlas of Poisonous Fish.') 



On the other hand, Briot thinks that it is quite different from 

 Trachinus, and that the effects produced are by secondary infection 

 of the mechanical wound caused by the spines. Brunton's descrip- 

 tion of the s^/mptoms in man might possibly be due to Trachinus 

 only, as he does not mention specifically whether it was Trachinus 

 or ScorpcBna which affected the person. His experiments on 

 animals with both fish appear, however, to have caused the same 

 symptoms. He pressed the spines of the poison organs against 

 the hind-limb of a guinea-pig or a rat. In a few minutes the 

 animal began to suffer pain and twitching in the injured limb, 

 followed by tremors and convulsions (if disturbed), and later by 

 death from collapse. 



The description which he gives of the symptoms in human beings 

 for either Scorpcsna or Trachinus is given below, but reference to 

 his original paper will, we think, convince the reader that he is 

 really dealing with a Trachinus sting. 



