9 8 



THE TOXINS OF THE HIGHER PLANTS AND ANIMALS 



-{-Signifies hemolysis. 

 Signifies no hemolysis. 



Cobra Hemolysin Test. 



1. Washing of Erythrocytes. The blood is collected into sterile flasks containing 

 sterile glass beads. It is shaken and thus defibrinated to prevent coagulation. 

 The defibrinated blood is next centrifugalized and the serum separated and drawn 

 off with a pipette. The red blood cell sediment is mixed with physiological salt solu- 

 tion and again centrifugalized. This procedure is repeated several times until all the 

 serum is removed. The red blood cells are used in a 5 per cent, suspension; i.e., i 

 part of washed erythrocytes suspended in 19 parts of saline. 



2. The Activating Agent. As an activating agent 0.2 c.cm. of serum or a o.i per 

 cent, lecithin solution is employed. The lecithin can be kept as a stock solution 

 consisting of i g. lecithin in 100 c.cm. of methyl alcohol. A o.i per cent, solution 

 of the stock mixture is made by mixing o.i c.cm. of the solution with 9.9 c.cm. 

 of physiological salt solution. 



3. The snake poison hemotoxin is resistant toward heat so that it may be heated 

 to almost 70 C. without interfering with its activity. Cobra poison contains the 

 greatest amount of hemotoxin. While i mg. of cobra toxin hemolyzes i c.cm. of 5 

 per cent, horse's red blood cells in five to ten minutes, a similar amount of viper toxin 

 requires thirty minutes for the same action. 



V. Dungern and Coca explain this type of hemolysis by the existence 

 of a ferment within the snake poison which breaks up the lecithin with 

 the liberation of oleic acid. This acid has long been known as a hemo- 

 lytic agent. The necessity for adding lecithin or serum to certain species 

 of blood is explained by the variability in the lecithin content of the 

 erythrocytes, or a variability in the lecithin union. 



