THE PHYSIOLOGY OF POISONING 191 



The venoms of Ancistrodon contortrix and^. piscivorus (Cbo- 

 TALiN^) proved entirely inactive. 



No CoLUBRiNB venom exhibited coagulant power, whatever the 

 dose employed. 



There is, therefore, a very decided difference between venoms 

 of divers origins as regards their effects upon the coagulation of 

 the, blood. 



Noc has determined more especially the coagulant action of 

 the venom of Lachesis lanceolatus (Fer-de-lance of Martinique) 

 upon 1 per cent, citrate-plasmas, 1 per cent, oxalate-plasmas, 4 per 

 cent, chloridate-plasmas, and upon blood rendered non-coagulable 

 by extract of leeches' heads. He found that, while weak doses of 

 venom (1 milligramme per cubic centimetre of horse- or rabbit- 

 plasma) produce coagulation in a few minutes in the citrate- 

 plasmas, chloridate-plasmas, or those treated with extract of 

 leeches, the doses of the same venom greater than 4 milligrammes 

 on the contrary suppress the coagulability of these plasmas, even 

 when there be added to them doses of chloride of calcium (for the 

 citrate- and oxalate-plasmas), or of distilled water (for the chlori- 

 date-plasma), or of fibrin-ferment (for the plasma treated with 

 leech-extract) sufficient to cause rapid coagulation in the control 

 tubes that do not contain venom. 



Noc also observed that the venom of the same species of snake 

 (Lachesis lanceolatus), when heated to 75° C, entirely loses its 

 coagulant properties ; and that, with a temperature of 58^ C, its 

 coagulant power already commences to diminish. When heated 

 for thirty minutes at a temperature of 65° C, a dose of 1 miUi- 

 gramme does not coagulate more than 1 c.c. of citrate-plasma 

 in one hour. G-. Larpb has likewise found that the venom of 

 Vipera ruSsellii loses its coagulant power when heated to 75 C. 



The coagulant substance in these venoms is precipitable by 

 alcohol at the same time as the neurotoxin and other active sub- 

 stances. The precipitate, when dissolved again in physiological 

 water, preserves &.U the properties of the original solution. 



