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 im 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 hemoglobin 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 amceboid 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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