Discovery of Poison Organs in Fishes. 255 



forms such, loose envelopes to them, that it is quite possible a 

 portion of such secretion might intervene between the spine 

 and its sheath, and, in that case, the spine would always have 

 a charge of virus ready for use. 



I always (he adds) favoured the idea that acrid mucus, 

 either normally so formed, or the result of excitement, was the 

 cause of the phenomena we have been considering until recently, 

 but having observed a new structure occupying the grooves in 

 the spines, which appears to be an organ destined to secrete a 

 specific poison, I have willingly given up the doubtful for what 

 appears to be a certain cause. 



And it was just this one mistake which prevented Mr. 

 Byerley and his friend Dr. Inman from arriving at probably the 

 true solution of this interesting anatomical point. 



Dr. Inman (Mr. Byerly tells us) was fortunate enough, not 

 having an immediate opportunity of examining the fishes in 

 their fresh state, to immerse them in spirit and water, in con- 

 sequence of which the gland became more opaque and denser. 



I (he adds) always had fresh fishes at hand, and in preparing 

 the parts for examination without having used spirit, must 

 have torn the gland from its usual resting-place. In fact what 

 Mr. Byerley saw only in spirit-specimens, was, in reality, no 

 organ at all, but the coagulated mucus fluid occupying the oper- 

 cular grooves and the space within the integument of the spine, 

 which only became visible from the effect of the spirit upon 

 the secretion. The structure which he figures and describes as 

 glandular, is merely the thickened appearance of this fluid 

 under the microscope. 



It remained for my distinguished friend and colleague Dr. 

 Albert Giinther, to give a complete demonstration of this most 

 interesting point of Ichthyological anatomy. He did so in 

 describing a new species of Batrachoid fish, from Panama, 

 before the Zoological Society, on 22nd March last. 



Dr. Giinther remarked that many fishes were dreaded on 

 account of their spine defences, such as the Sting-rays and 

 Siluroid fishes, and some scaly fishes, as the Weevers. Exag- 

 gerated accounts, no doubt, were often circulated of the venom- 

 ous nature of these fishes ; still, in some cases, it seems certain 

 the wounds must have been poisoned. No trace, however, of 

 an organ secreting a poisonous substance could be found, and 

 all handbooks of comparative anatomy denied the presence of 

 such a gland in any fish. 



The axil of the pectoral fin of many Siluroid fishes, Dr. 

 Giinther observed, contained a cavity with a mucous fluid, 

 which might be introduced into a wound by means of the 

 pectoral spine like the poisoned arrow of the Bushman. He 

 had no doubt of the poisonous nature of the contents of 



