1904.] Study of the Action of Sea-snake Venoms. 105 



The minuteness of these doses proves that sea-snake venom is the 

 most lethal of all substances whose lethal power has been determined. 



1. (b) Enhydrina Valakadien venom extracted by us from dried 

 glands : 



This proved to possess a lethality rather less than half that of the 

 expressed venom. 



2. Expressed Enhydris Curtus venom : 



M.L.D. for rats between 0*0005 and 0*0006 gramme per kilo. 



The minimum-lethal doses for rabbits and cats likewise proved to be 

 higher than those of the Enhydrina venom. 



We mention this difference in lethality between Enhydrina and 

 Enhydris venoms without laying stress on it, as we are unable to be 

 certain that it was not due to some change which the Enhydris venom 

 had undergone. 



Comparison of the Relative Lethality of Enhydrina and Cobra Venoms 

 for Various Animals. An active specimen of Cobra venom was taken, 

 the M.L.D.'s of which for rats, rabbits, and cats had been found to be 

 0'0005, O'OOOG, and O'OIO gramme respectively, per kilo, of body 

 weight of animal. Expressing the smallest M.L.D. in the case of each 

 venom as the unit, we find the relative lethality for the different kinds 

 of animals to be the following : 



Cobra venom, rats = 1; rabbits =1*2; cats =20. 

 Enhydrina venom, rabbits = 1 ; rats = 1*5 ; cats = 3 '3. 



The difference in the cat-rodent relationship is especially suggestive 

 of a marked difference in the physiological actions of the two venoms, 

 and the reversal of the rat-rabbit relationship is also of some signifi- 

 cance, in the same connection. 



Symptoms of Sea-snake Poisoning in Animals. In the main these 

 symptoms resemble those of cobraism, but the dyspnoea is more urgent, 

 probably because the heart is not directly affected by the venom, as it 

 is in cobraism. 



We have observed that lid-rise of the lower lid is a constant sign in 

 Enhydrina poisoning, as it is in the course of poisoning by the venom 

 of the Cobra and Krait. It appears to be produced by an elastic 

 rebound of the lid, caused by paralysis of its depressor muscle, probably 

 central in origin, and it is closely comparable with the ptosis met with 

 in cobraised men and monkeys. 



Of the two points dealt with above, the first suggests a difference 

 between the actions of Cobra and Enhydrina venoms, and the second a 

 resemblance between their actions. 



The Antagonism of Calmette's Serum and Enhydrina Venom Compared 

 with that between Cobra Venom and the same Serum. A sample of 

 Calmette's serum which proved to be definitely antagonist to Cobra 



