420 .1 >r. L. liugers. On the Physiological Action [Xov. 10, 



the class, only in addition it may cause a chronic affection. This 

 difference I find is due to its containing some of the Yiperine element 

 in addition to the Colubrine one, and it may thus produce intra- 

 vascular clotting in large doses. The blood-pressure and respiratory 

 tracings show the typical respiratory paralysis of Colubrine venoms, 

 but in addition it causes a marked primary fall of blood pressure, 

 while artificial respiration fails to keep the circulation going, as with 

 the other Colubrine venoms. Heating to 90 C. for a short time 

 greatly lessens this effect on blood pressure and renders artificial 

 respiration much more efficacious, owing to the Viperine element 

 being more readily destroyed by heat than is the Colubrine one. 

 The venom also produces motor end-plate paralysis like the other 

 Colubrines. 



III. The Bungarus ccendeu* or Krait is a small but deadly snake. 

 The symptoms produced by it are identical with those of Cobra venom, 

 and a blood pressure and respiratory tracing shows that it paralyses 

 the central respiratory centre in the same way as the latter. Its action 

 on the phrenic end-plates is, however, somewhat less marked than that 

 of the other Colubrines. 



We see, then, that each of these venoms causes death by paralysing 

 the respiratory centre just like Cobra and Sea-snake venoms, but in 

 addition the venom of the Banded Krait has a Viperine element which 

 produces a primary fall of blood pressure, and sometimes intra-vascular 

 clotting, thus resembling the Australian Colubrine snake, the Pnewler-hi* 

 porphyacus. 



Calmette's antivenin has an undoubted specific action against Cobra 

 venom. It, therefore, becomes a matter of practical importance to 

 ascertain if it is also effective against the other Colubrine ajid Sea 

 snakes, whose lethal action is identical with that of the Cobra. A 

 series of experiments have been carried out by mixing about ten times 

 a fatal dose of venom with different quantities of the serum for half 

 an hour before injection and noting the results. It was first tested 

 against the common variety of the Cobra, which it neutralised more 

 readily than it did the venom of a less common kind. It acted next 

 best against the Hamadriad or King Cobra, and only a little less so in 

 proportion to its toxicity, against the Smhydrina bengak'nsis, a Sea snake. 

 In the case of the Krait its action was much more feeble, although still 

 distinct, while in tlyit of the Banded Krait it prevented all Colubrine 

 symptoms, if a sufficient dose was used, but the animals died 2 4 

 days after with symptoms of chronic Viperine poisoning, thus confirming 

 my conclusion that this venom is a mixture of the two elements. 



These results are of great interest in showing that the serum has a 

 definite action in neutralising the respiratory paralysing poison of all 

 the Colubrines and the Hydrophidse, although it will require to be made 

 stronger than it is. at present, if it is to be relied on to cure the bites 



