On Inflammation in Fishes. 229 



their American brethren Physick and Levert, on the probable 

 benefit likely to result in the treatment of wounds, from 

 substituting metallic threads for those of silk or hemp 

 usually employed. They were led to this opinion by ob- 

 serving the small amount of irritation sometimes resulting 

 from the presence of a metallic substance, such as a bullet, 

 in the textures of the body. I was then engaged with 

 Professor Simpson in experimenting upon animals, and 

 endeavouring with him to collect reasons why the metallic 

 thread should supersede the silk one. 



As an instance of how little irritation is caused by metal 

 left in living tissues, I instanced the practice of marking- 

 par, grilse, &c, with wire, and these marks being found in 

 the fish after months or years ; whereas, had the material 

 of the marks been non-metallic, they would most probably 

 have cut or ulcerated out of the tissues. I was told that 

 this was no argument, as fish did not inflame — at all events, 

 that their tissues did not ulcerate or suppurate — and I was 

 referred to the following passage in Macartney's treatise 

 upon inflammation : "In neither of the two classes of 

 vertebrate animals with cold blood do I believe it possi- 

 ble to produce the genuine effects of inflammation. In 

 conducting some experiments on the swimming-bag of 

 fishes, I was surprised to find that the wound made into 

 the belly did not inflame. I was therefore curious to know 

 what injuries fishes would bear without producing inflam- 

 mation. Having taken some living fishes from the water, 

 I introduced pieces of wire beneath the skin and amongst 

 the muscles of the body ; the fishes were then returned to 

 the water, and on examining them several days afterwards, 

 I found that no suppuration had taken place. The tracks 

 of the wounds were pale and smooth, and only moistened 

 with a serous fluid, and none of the usual appearances of 

 inflammation were visible. A very common occurrence in 

 fishes is the existence of worms, which perforate the tunics 

 of the alimentary canal, without producing any change of 

 structure, except an increased vascularity around the per- 

 forations. The reproductive power of fishes is confined to 

 the fins, which are sometimes regenerated after being lost 



