On separating the coagulable albumins of the venoms of COLUBRIDÆ, by heating to 72° C., followed by filtration, we obtain a perfectly limpid liquid, which is no longer injured by boiling, and in which the toxic substance remains wholly in solution. The albuminous precipitate, when separately collected and washed, is no longer toxic. The clear liquid, after being filtered, is again precipitated by absolute alcohol, and the precipitate, redissolved in an equal quantity of water, is just as toxic as the original filtered liquid. The venoms of VIPERIDÆ, when coagulated, by heating them to a temperature of 72° C., and filtered, are almost always inert. The albuminous coagula, if washed, redissolved in water, and injected into the most sensitive animals, produce no harmful effect whatever. * * * * * The results of dialysis likewise differ when we experiment with the venoms of COLUBRIDÆ and VIPERIDÆ. The former pass slowly through vegetable membranes, and with greater difficulty through animal parchment. The latter do not dialyse. Filtration through porcelain (Chamberland candle F) does not sensibly modify the toxicity of the venoms of COLUBRIDÆ; on the contrary, it diminishes that of the venom of VIPERIDÆ by nearly one-half. By using a special filter at a pressure of 50 atmospheres, C. J. Martin has succeeded in separating from the venom of an Australian _Pseudechis_ two substances: a non-diffusible _albuminoid_, coagulable at 82° C., and a diffusible, non-coagulable _albumose_. The former produces hæmorrhages; the second attacks the nerve-cell of the respiratory centres. * * * * * All venoms exhibit most of the chemical reactions characteristic of the proteids:-- _Millon’s reaction._ _Xantho-proteic reaction_ (heating with nitric acid and subsequent addition of ammonia = orange coloration). _Biuret reaction_ (caustic potash and traces of sulphate of copper). _Precipitation by picric acid_, disappearing on being heated, reappearing when cooled. _Precipitation by_ saturation with _chloride of sodium_. _Precipitation by_ saturation with _sulphate of magnesium_. _Precipitation by_ saturation with _ammonium sulphate_. _Precipitation by a 5 per cent. solution of sulphate of copper._ _Precipitation by alcohol._ According to C. J. Martin and MacGarvie Smith, the albumoses of the venoms of COLUBRIDÆ are _hetero-albumoses_, _proto-albumoses_, and perhaps _deutero-albumoses_ in small quantities. They can be separated in the following manner:--