1878.] 



Prof. Pedler on Cobra Poison. 



21 



therefore, unable to obtain any satisfactory result by the aid of 

 dialysis. 



I have satisfied myself by numerous experiments that the reported 

 remedy for snake bite, ammonia, has no action chemically upon the 

 poison, but that, if anything, the addition of this substance to the 

 poison before hypodermic injection rather increases the rapidity of the 

 action of the poison, and in no instance does it induce any modification 

 of the poisonous action. 



Whilst experimenting with the poison, it struck me that it was pos- 

 sible that, as in the case of many organic poisons, the nitrogen might 

 be in the triad condition, and that it might be possible to modify the 

 poison by the action of ethylic iodide or other substances, as has been 

 done in the case of some alkaloids. Ethylic iodide was digested with 

 the poison, and the residue, which had increased in weight, when phy- 

 siologically tested, was found to be very much less active than usual, 

 although still poisonous ; the sample taking about five times as long 

 to kill as fresh cobra poison. Another sample of poison was treated 

 with hydrochloric acid, and evaporated spontaneously, and the residue 

 was very much less active than ordinary poison, and I have found that 

 even the addition of a small quantity of this acid to a solution of the 

 poison before injection materially retards the poisonous action ; for a 

 quantity (3 milligrams) of poison, which under ordinary circumstances 

 would kill a chicken in about half-an-hour or forty minutes, after the 

 addition of 0"2 c.c. of hydrochloric acid took 1 hour 6 minutes to pro- 

 duce the same effect. The poison treated with hydrochloric acid, 

 when evaporated very slowly in vacuo, shows distinct traces of crystals ; 

 but there still remains a large quantity of amorphous soluble matter, 

 from which, when working on a small scale, as from the nature of the 

 subject I was obliged to do, the crystals cannot be separated. 



As hydrochloric acid has some apparent chemical action on cobra 

 poison, I tried the effect of a number of chemical compounds on this 

 substance, and by a natural sequence of ideas, having found that 

 hydrochloric acid had a tendency to act in the required direction, 

 amongst them I employed platinum tetrachloride, and found that 

 this yielded excellent results, and gave indications of what might be 

 called a chemical antidote. 



The following is a typical experiment. A quantity of fresh cobra 

 poison was precipitated with alcohol, and the precipitate of albuminous 

 matter well washed, then dissolved and tested, and found to have very 

 slight poisonous action only, the alcoholic filtrate was then acidified 

 with hydrochloric acid, and a solution of platinum tetrachloride added, 

 when a small quantity of a yellow amorphous precipitate was formed ; 

 the solution on evaporation in vacuo yielded a semi-crystalline residue, 

 from which the excess of the platinum salt was removed by washing 

 with dilute alcohol ; O'l gram of the solid platinum compound, which 



