SNAKES OF CEYLON. 479 



upon for their activity. After a period of activity, the 

 pockets, which converge forwards and inwards towards the 

 axis of the gland, become distended with poison, and this is 

 poured into the central duct. At the posterior pole the gland 

 ends in a downward projecting lobe. The fibrous capsule 

 dips into the gland, just in front of this lobe, to form a furrow 

 for the attachment of an important muscle, the masseter. 

 This muscle originates from the postfrontal bone and the 

 ridges on the parietal, and is somewhat fan-shaped. Its 

 fibres converge, and pass first backwards over the superior 

 and internal surfaces of the gland, then downwards behind 

 its posterior pole, and finally forwards to be attached to the 

 furrow, or dimple in front of the lobe. The muscle, in fact, 

 embraces a large part of the gland surface, and in contraction 

 squeezes it much in the same way as the hand operates on a 

 bicycle horn, the result being that poison is driven forwards 

 into the duct to pour finally into the mouth. The neck of 

 the gland consists of a sheath which is the direct continuation 

 of the capsule surrounding the body, but is much thinner. 

 Centrally is the poison duct, and intermediate between the 

 sheath and the duct a series of mucous glands. These are 

 placed at right angles to the axis of the duct, and discharge 

 their mucous into that channel, where it mingles with the 

 poison proper. In section the gland appears to the naked 

 eye much like a sponge. 



(b) Physical Characters : Cobra venom, when freshly secreted, 

 is a clear, amber-coloured, very viscid fluid, with a specific 

 gravity of 1,050. It resembles olive oil in appearance and 

 consistency, and soon solidifies into an amorphous brittle 

 mass, Assuring in all directions, and losing from 60 to 75 per 

 cent, of its weight in the process of drying. 



Lieut. -Colonel Glen Liston has very kindly weighed me a 

 drop of fresh cobra venom in the balance at Parel Laboratory, 

 and find it weighs approximately 35 mgms. Allowing a loss 

 of 68 per cent, in drying, the residue of one drop would weigh 

 11 mgms. It is somewhat remarkable that a drop of olive 

 oil, to which I have compared cobra venom in appearance and 

 consistency, only weighs 6 mgms. in the same balance at Parel. 



