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Some Experiments with the Venom of Causus rhombeatus. 

 By H. E. Arbuckle, M.B., West African Medical Service. 



(Communicated by A. Alcock, CLE., F.R.S. Eeceived November 5, — Read 



December 9, 1909.) 



In Sierra Leone there are numbers of a small viperine snake of the 

 genus Causus, known locally as " chicken snakes," of which it has been my 

 good fortune to get several fine specimens. The largest was 463 mm. long, 

 the tail being only 35 mm. 



The poison-gland is remarkably long, practically one-fourth the length of 

 the snake. It lies dorsally, immediately beneath the skin, and shows no 

 indication of attachment to any other structure. It is flat and ribbon-like, 

 with a maximum breadth of about 6 mm. It is of a greyish-pink colour, 

 spotted in its middle third. It stretches as far back as the jDOsterior level of 

 the heart. At the quadiato-mandibular .joint it narrows into a flat duct 

 which becomes attached to underlying structures and is covered by fascia. 

 The duct ends in an ampulla which just touches the maxilla when the fang 

 is erected. The entire gland can be seen by merely reflecting the skin. 



The venom seems to be ejected by the contraction of the gland itself. In 

 a chloroformed snake, with the gland exposed by reflection of the skin, 

 a slight pinch of the gland with the forceps causes a vigorous contraction. 

 If the end of the gland be ])inched, a peristaltic contraction forwards takes 

 place, towards the duct, and some venom is ejected. If the gland be 

 squeezed in the middle, a peristaltic contraction forwards occurs on both 

 sides of the forceps. 



In the experiments liere recorded the venom was used in three ways — 

 fresh venom dissolved in sterile salt solution, dried venom dissolved in sterile 

 salt solution, and the alcoholic precipitate of venom re-dissolved in sterile 

 salt solution. 



The action of the venom, which seemed the same in all three methods of 

 administration, was shown in local eccliymosis, and in drowsiness and 

 muscular weakness. In al)out half the cases tlierc was marked slowing of 

 the respiration with great difficulty in inspiration. Post-mortem examination 

 showed in most cases su])erficial luumorrliagc into the viscera, especially the 

 licart and lungs, th(! lungs being in two cases lilled with fluid and deeply 

 discoloured by hn'inoi rhage. 



Expei imiMit 1. — After killing the snake the two glands were at once 

 removed and s(jueeze(l into sterile salt solution in a hypodermic syringe, and 



