1878.] 



Prof. Pedler on Cobra Poison. 



23 



an antidote (if possible) rather than the solution of the purely chemical 

 question. 



The experiments which I have made to investigate the physiological 

 portion of the subject, naturally divide themselves into three distinct 

 series : the first, in testing the action of graduated doses of the pure 

 fresh poison hypodermically injected into animals ; the second, in the 

 injection of cobra virus mixed with dilute aqueous solution of plati- 

 num tetrachloride ; and the third, in the action of the platinum salt 

 on animals previously poisoned by fatal doses of the virus. 



In my preliminary experiments, I assured myself that fresh cobra 

 poison mixed directly with a small quantity of solution of platinum 

 tetrachloride almost entirely loses its poisonous properties. In order 

 to investigate this thoroughly, I selected chickens as good subjects to 

 work on, and first ascertained the action of pure fresh cobra poison in 

 various quantities, hypodermically injected, on these animals. The 

 summary of the results which I obtained are shown in Table A, whilst 

 the details of the experiment are described in an Appendix* which 

 contains the description of most of the more important physiological 

 experiments made during this investigation. 



Table A. — Action of Cobra Poison, hypodermically injected, on Chickens. 



No. 



Amount of Dried Poison used. 



Duration of Experiment. 



Result. 







Hours. 



Minutes. 





1 







17 



Death 



2 



5 „ 





31 





3 







, 38 





4 





i 



12 





5 





i 



34 





6 





2 



40 



j) 



7 





1 



52 



;> 



8 





The animal 



was almost 



Recovered 







insensible for 12 hours. 





From this table, it appears that a quantity of T T y milligram of pure 

 dry cobra poison is sufficient to kill with certainty a healthy chicken, 

 while 2^ of a milligram, when injected, produced such an effect, that 

 for twelve hours the life of the chicken was despaired of ; in larger 

 doses the action of the poison is proportionately more rapid, until with 

 a few milligrams death results within a few minutes. 



A second series of experiments was then tried, by taking solutions 

 of weighed quantities of the same sample of cobra poison as was used 

 in the first series, mixing with known weights of platinum tetrachlo- 

 ride, and injecting. The experiments are subdivided into two classes, 

 according to slight variations in the method of working ; in some 



# This Appendix is deposited in the Archives of the Royal Society. 



