254 Discovery of Poison Organs in Fishes. 



The thumb now began to swell, and exhibited an inflamma- 

 tory blush, extending upwards to the wrist. 



The pain was now distinctly throbbing and very excrucia- 

 ting. In this state it continued for about an hour, when 

 the pain began somewhat to subside, the swelling and redness 

 still continuing. In about an hour and a half the pain was 

 nearly gone. Next morning the swelling of the thumb had but 

 slightly diminished, and was in some degree diffused over the 

 back of the hand, the thumb continued red and hot, and pain- 

 ful on pressure over the metacarpal bone. In a few days the 

 swelling had completely subsided j but the pain on pressure 

 continued for more than a week.'" 



The spines of the opercula in this fish, of which we have 

 two species (the Trachinus viper a and the Trachinus draco) „ 

 are deeply grooved along their edges, each groove terminating 

 at the base of the spine in a conical cavity. The integument 

 is continued over the spine to within a very short distance of 

 the point, forming a complete sheath for nearly its entire 

 length, and converting the grooves at each side into perfect 

 tubes, extending from the base to the point of the spine. The 

 result of this arrangement is a structure beautifully adapted 

 for the conveyance of a fluid from the base to the apex of the 

 spine. 



The spines of the dorsal fin in the Weevers are also grooved, 

 but the grooves become superficial, and disappear towards the 

 base, and do not terminate in cavities similar to those at the 

 bases of the spines of the opercula. Professer Allman dM not 

 succeed in detecting any specific gland connected with this 

 apparatus, but at the bottom of each of the conical cavities of 

 the opercula he noticed a small pulpy mass, which he considered 

 might possibly bo a glandular structure ; but he adds, " In 

 ascribing to it tho property of secreting the virus, I do 

 nothing more than hazard a conjecture." 



The next recorded observations upon this subject are by 

 Isaac Byerley, Esq., in tho Proceedings of the Liverpool 

 Literary and Philosophical Hociety, vol. i. p. 150, May, 1849. 



Mr. Byerley records carefully the effects produced by 

 wounds from these fishes, and gives also sections of the spines, to 

 show the side grooves which Dr. Allman had already described. 

 Ho says it has been suggested that tho fish is capable of 

 secreting mucus from its skin of great acridity, which, follow- 

 ing the spine into the wound, might produco the effects men- 

 tioned. A large: quantity of mucus is secreted by means of 

 glands under tho skin in nil fishes, but it would, Mr. Byerley 

 considers, bo very remarkable that the Trachinus alone should 

 secrete it of so irritating a quality. The upper part of tho 

 membrane covering the spines, especially the opercular ones, 



