CHAPTER XVI. 

 VENOM HAEMOLYSIS AND VENOM AGGLUTINATION. 



THE EFFECTS IN VIVO AND IN VITRO. 



Fontana, who observed the loss of coagulability of the blood in cases of 

 death from viper poisoning and the anticoagulating effect of that venom upon 

 the shed blood in vitro, failed to discover any alteration of the corpuscles. 

 Weir Mitchell, who noticed similar effects of crotalus venom in cold-blooded 

 as well as warm-blooded animals, saw no perceptible changes in the cellular 

 elements of the blood, either examined immediately after death or when the 

 blood and venom were mixed in vitro, at least not within any brief period of 

 time, as half an hour. He emphasizes, however, that it is a question open to 

 further study whether or not this direct contact would affect them after a 

 longer time. In his subsequent investigations, once with Reichert and again 

 with Stewart, Mitchell found that the venom of Crotalus destroys blood 

 corpuscles after a long contact in a zone of suitable concentrations of the 

 venom. This observation is very important, as he shows there that a too 

 strong solution of venom again fails to bring about destruction of the corpuscles 

 in vitro, and this phenomenon received confirmation by many later investi- 

 gators with the venoms of other species of snakes, for example, cobra venom. 

 From the blood of guinea-pig, rendered less coagulable or incoagulable by 

 the crotalus venom, Mitchell obtained beautiful crystals of haemoglobin which 

 in no way differed from those prepared from the blood of the normal guinea-pig. 



Weir Mitchell and Reichert (1886) described a peculiar effect of crotalus 

 venom upon the shape of red corpuscles. Under the influence of the venom 

 the erythrocytes first lose their biconcavity and become spherical, without 

 parting with their pigment. They also exhibit great adhesiveness, arranging 

 themselves into aggregations of various sizes and shapes. The corpuscles 

 comprising these groups sometimes appear to fuse so that their outline can 

 not be determined. (This phenomenon was later confirmed by Flexner and 

 Noguchi, who called it venom-agglutination.) This remarkable condition 

 passes away after a short duration, the corpuscles appearing again in separate 

 spherical form. 



The amoeboid movements of leucocytes are seen to be quickly suspended 

 in the venom solution. 



Fayrer and Brunton (1874) failed to discover any definite alteration of 

 the blood corpuscles when death resulted from cobra venom, except less 

 inclination to form rouleaux and more marked crenation of the corpuscles. 



Lacerda (1854), working with a species of Lachesis, probably Lachesis 

 urutsu, mentions crenation of the red corpuscles in chronic poisoning. Some 



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