508 poisons : their effects and detection. [§§ 665, 666. 
The latest observer of the cobra poison, Edwin Stanton Faust, 1 claims 
to have shown that the essential constituent of the cobra poison is a 
nitrogen-free substance, belonging pharmacologically to the group of 
the picrotoxins, sapotoxins, and sphacelo-toxins. To this substance he 
gives the name of “ ophiotoxin ” ; he has obtained it in aqueous solution, 
but directly the aqueous solution is concentrated in a vacuum, the 
white residue obtained is in most cases inactive. The solution froths 
on shaking ; if injected subcutaneously it has but little action ; on the 
other hand, if injected intravenously the ordinary effects of cobra 
poison are produced. Hence Faust appears to believe that the poison of 
the cobra is some compound of his ophiotoxin and an albuminoid body, 
the combination being easily dissolved. He thinks that there is some 
analogy between the cobra poison and the jalapin-elaterin group, in 
which the free acids and their salts are inactive ; while, on the other 
hand, the anhydrides are active. 
The blood of the cobra is also poisonous. A. Calmette 2 has found 
that 2 c.c. of fresh cobra blood injected into the peritoneum of a rabbit 
weighing T5 kilo, causes death in six hours ; the same dose of the 
defibrinated blood injected into the veins is fatal in three minutes. 
§ 665. Fatal Dose. —From one of the senior author’s experiments on 
cats, rabbits, and birds, it seems probable that the least fatal dose for 
cats and rabbits lies between -7 and *9 mgrm. per kilo., and for birds 
somewhere about *7 mgrm. per kilo, of the dried poison ; the venom con¬ 
tains about 60 per cent, of albuminous matter and about 10 per cent, 
of poisonous substance ; therefore the lethal power is represented by 
something like -07 to -09 mgrm. per kilo., if the pure toxic principle 
free from albumen and diluting impurities be considered. Calmette 
calculated the fatal dose for a man at 10 mgrms., Fraser 3T7 mgrms., 
and Elliott about 30 mgrms. 
§ 666. Effects on Animals. —There has been much exact physio¬ 
logical work done on the cobra poison since the last edition of this 
work. One of the most complete researches is that by H. R. Elliott; 3 
he has confirmed the fact that cobra venom raises the blood-pressure ; 
this action can be traced in the vessels of the frog, down to dilutions of 
1 in ten million. If the solution is concentrated, it acts directly on 
the isolated frog’s ventricle, killing it in systole ; but if the solution is 
weak, the action of the heart is stimulated ; this brings cobra venom 
into line, pharmacologically, with the glucosides of the Strophantin 
group. Elliott found that atropine sulphate and cobra venom in the 
same solution intensify each other. 
Cobra venom acts powerfully on the mammalian heart ; the action 
is dual— 
1 Die thierischen Gifte, Braunschweig, 1906. 
2 Compt. rend. Soc. de Biol., 1894. 3 Phil. Trans., 1905. 
