THE VENOM 



be made to the original papers given in our list at the end of this 

 chapter. 



(h) The Leucolysins. — -Weir Mitchell and Reichert had noticed in 

 their researches that the mobility of leucocytes absolutely ceased 

 in cro talus poisoning. Martin studied this carefully with Pseu- 

 dechis venom, and says that for the first fifteen minutes he could 

 see no change in the white cells, but they exhibited no amoeboid 

 movements. At the end of this time the nuclei in some of them 

 were very distinct, as if fixed by acetic acid. They then became 

 intensely granular, and soon began to swell, and their outlines to 

 grow less distinct, until they disappeared, leaving only a small 

 heap of granules. 



Flexner and Noguchi studied this phenomenon, and found that 

 leucocytes with large coarse granules were most quickly affected; 

 next came the fine granular varieties; and last of all the lympho- 

 cytes. They found cobra poison much more vigorous than that 

 of crotalus. As to the leucolysins, they proved that they were 

 separate from the haemolysins by treating washed red corpuscles 

 with copperhead venom until the supernatant fluid, after centri- 

 fugalization, ceased to have any effect on red cells. This fluid was 

 then brought into contact with leucocytes, when lysis without 

 agglutination took place. If, however, washed leucocytes were 

 treated first, the supernatant fluid was found to be actively hsemo- 

 lytic. They therefore concluded that the haemolysins were distinct 

 from the leucolysins, but that the agglutinins were probably the 

 same. 



We are not aware of further researches as to the nature of the 

 leucolysins, though obviously such researches are required. 



(c) Hcemorrhagin.— Weir Mitchell and Reichert, by observing a 

 mesentery moistened with crotalus-venom, came to the conclusion 

 that the blood escaped from the vessel owing to damage to the wall. 



Flexner and Noguchi found that by heating crotalus-venom to 

 75° C. for thirty minutes, this hsemorrhagic power was lost, and 

 along with it most of the toxicity, as ten or twenty M.L.D. were 

 required to cause death with symptoms resembling cobra-venom. 

 They conclude that this death must be due to the neurotoxic or 

 hsematoxic properties (haemolysins and agglutinins) in the venom, 

 and that, as the latter can be eliminated without any apparent loss 

 of toxicity, it must be due to the neurotoxins. 



The toxic principle lost by heating to 75° C, Flexner and Noguchi 

 called hsemorrhagin. They studied its action in the mesentery by 

 injecting the venom into the peritoneal cavity, or placing a minute 

 particle of the dried poison on the exposed mesentery, and then 

 removing specimens, which they fixed in Zenker's fluid, cut into 

 sections, and stained with baematoxylin and eosin. They found 

 that the extravasation of blood took place not by diapedesis, but 

 through actual rents in the walls. These rents are not simple 

 ruptures, but are apparently due to a cytolytic action upon the 

 endothelial cells of the capillaries and the walls of the small veins. 



