8 THE VENOMS OF CERTAIN THANATOPHIDE^E. 



clear and tintless as water ; but when re-exposed to the air once more became 

 yellow throughout, within one or two hours. 



The yellow pigment of Cobra poison, when the dry poison was dissolved in water, 

 does not rise in the tube or disappear, but remains unaltered. It is desirable to 

 repeat these observations with fresh Cobra venom. 



The cause of the disappearance and reappearance of the coloring matter of 

 venom we have not been able to explain to our satisfaction, and it is one of the 

 questions left open for inquiry. 



The Specific Gravities of Venoms. — The specific gravity of the venoms of our 

 own serpents is as follows : — 



Crotalus horridus ........ 1.054 



Crotalus atrox ........ 1.077 



Crotalas adamanteus 1.061 



Ancistrodon piscivorus ....... 1.032 



The specific gravity of Cobra venom is given by Wall at 1.058. 

 As to that of the Indian viper we can find no statement. 

 The losses of venom on drying were as follows: — 



C. adam. 25.15 per cent. 



C. atrox 25.16 



Ancis. piscivorus . ..... 27.42 " 



