RAYS 75 



pierce armour like an arrow, it is as strong as iron, yet possesses 

 venomoub properties." 



It is of some interest to find Pliny suspecting the presence 

 of venom, for, until a few years ago, almost all writers on 

 fishes were agreed that no specific poison existed, and that 

 the inflamed nature of the wound and the acute pain and 

 paralysis was due merely to the irregular cut made by the 

 saw-edged spine, aggravated by the slime and loose cuticle 

 covering it. Recently, however, it has been shown that the 

 narrow groove running along -each edge of the spine contains a 

 fine glandular tissue, that can scarcely be detected without 

 the aid of a microscope. The cells composing this tissue 

 secrete a virulent venom, and when they are ruptured this is 

 squeezed out and runs down the groove and enters the wound. 



The effect of the poison on man varies somewhat with the 

 species, as well as with the size and general condition of the 

 fish and the extent of the wound. It may be very severe, and 

 on rare occasions has been known to be fatal. An Italian 

 scientist describes how he saw " a young man become extremely 

 pale and fail down almost senseless for a few minutes, from 

 having received only a very small puncture while he was in 

 the act of passing a Trygon, weighing 3 kgrm., from one 

 person to another ". Dr. Schomburgk mentions a fresh- 

 water Sting Ray found in British Guiana- which was responsible 

 for the death in violent convulsions of a colonist, whilst the 

 two natives who accompanied him were wounded in the feet, 

 became seriously ill, and only recovered the use of their 

 feet after a long period of suffering. Many other cases of 

 severe trouble, including gangrene and tetanus, following a 

 wound by one of these " stings " have been recorded. It 

 has been stated that some Malays fastened two spines to a 

 pole and stabbed a horse, which became delirious, and was 

 only saved by having the wounds enlarged and treated with 

 iodine. Treatment of wounds, if carried out at once, is 

 simple and efficacious. The injection of a few minims of a 

 5% solution of permanganate of potash (or " Condy's 

 Fluid ") will relieve the pain and prevent inflammation. 



The food of these fishes is very similar to that of the True 

 Rays, consisting mainly of other fishes, crustaceans and 

 shellfish. 



