162 VENOMS 



on the contrary, it diniinislies that of the venom of Viperid.e 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 

 Pseiidechis two substances : a non-diffasible alhuminoid, coagulable 

 at 82° C, and a diffusible, non-coagulable albumose. The former 

 produces haemorrhages ; the second attacks the nerve-cell of the 

 respiratory centres. 



All venoms exhibit most of the chemical reactions characteristic 

 of the proteids : — 



Milloiis reaction. 



Xantlio-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, re- 

 appearing when cooled. 



Precipitation by saturation with cJiloride of sodium. 



Precipitation by saturation with sulphate of magnesium. 



Precipitation by saturation with ammonium sulphate. 



Precipitation by a ly pier cent, solution of sulphate of copper. 



Precipitation by alcohol. 



According to C. J. Martin and MacGarvie Smith, the albumoses 

 of the venoms of Colubrid^e are hetero-albumoses, proto-albumoses, 

 and perhaps deutero-albumoses in small quantities. They can be 

 separated in the following manner: — 



The solution of venom is heated to 90' C, and filtered in order 

 to separate the albumins coagulable by heat. The filtrate, saturated 

 with sulphate of magnesium, is shaken for twelve hours. By this 

 means there is obtained a flocculent precipitate, which is placed 

 upon a filter and washed with a saturated solution of sulphate of 

 magnesium. The filtrate is dialysed for twenty- four hours in a 

 stream of distilled water, and then concentrated, likewise by dia- 

 lysis, in absolute alcohol. Thus we obtain a few cubic centimetres 



