VENOM HAEMOLYSIS AND VENOM AGGLUTINATION 179 



The toxoid formation of haemolytic principles, first observed by Myers with 

 the cobra venom, has been confirmed by Flexner and Noguchi with the Ameri- 

 can venoms. They did not find such rapid deterioration as was mentioned 

 by Myers. They found that hydrochloric acid in the concentration of 2 to 

 3 per cent caused only a slight deterioration of haemolysins after 48 hours. 



Lamb (1903) estimated the haemolytic value of cobra venom for a number 

 of the bloods of different animals by using the calorimetric measurement in 

 small test-tubes containing a known quantity and the red corpuscles in 

 question. He brought out no specially new point as to its behavior upon the 

 red cells, but he has shown that i per cent solution of cobra venom resists 

 the heating to 73 C. much better than o.i per cent solution of the same venom. 

 With unheated venom 0.005 c - c - f the blood suspended in 0.5 c.c. isotonic 

 salt solution was dissolved by 0.015 m - The heating of i per cent solution 

 of the venom raised this minimal complete haemolytic dose to 0.0312 mg., 

 while that of o.i per cent solution was raised to 0.25 mg. 



Now, coming to the haemolytic property of the daboia venom, Lamb found 

 a somewhat singular phenomenon, namely, that this venom, while a powerful 

 destroyer of the red corpuscles in vivo, did not readily dissolve the blood 

 corpuscles when the cells were directly mixed with the venom in a saline 

 solution in vitro. This fact has also been observed by Cunningham and 

 emphasized especially by Stephens and Myers. Lamb found that in order 

 to start haemolysis of any kind of blood it was necessary to have the toxicity 

 of the saline medium somewhat below the iso toxicity, so as to produce a par- 

 tial destruction of the corpuscles before the venom is introduced, recollecting 

 also that Stephens and Myers noticed that the addition of the normal horse 

 serum accelerated the haemolysis with this venom. 



Weir Mitchell's phenomenon, namely, non-haemolysis by too strong a con- 

 centration of venom, has also been observed with the daboia venom in vitro. 

 As to the resistance of the haemolytic principle of the daboia venom, Lamb 

 finds that it differs from that of the cobra venom, as the former loses its activ- 

 ity completely when heated to 73 C. in a o.i per cent solution, whereas only a 

 certain diminution of power takes place in the latter venom. Another point 

 of difference between these two venoms is the far more powerful haemolytic 

 action in vivo possessed by the daboia venom. 



Noc, working with a large variety of snake venoms, established the fact 

 that the phylogenetic relation between the main families and genera of poi- 

 sonous snakes is not merely an anatomical and morphological factor, but 

 also a biological factor, for he found that the activity of the haemolytic prin- 

 ciples of their venoms obeys the linear course and rank to which each snake 

 is assigned in the natural system. Noc's experimental data bearing on this 

 point are simple. He determined the length of time required by i mg. of 

 each venom to haemolyze completely i c.c. of 5 per cent suspension of the 

 washed corpuscles of horse in 0.9 per cent salt solution in the presence of 

 0.2 c.c. of the normal horse serum heated previously to 58 C. It was neces- 

 sary to add this amount of the heated horse serum to obtain haemolysis, as 



