342 BIOLOGICAL EFFECTS OF RADIATION 



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+ ^" "^j^^" "4 + ," or similarly unsatisfactory terms. For 

 this reason very few protocols are given here. Much of the work was 

 done in the youth of immunology and could profitably be repeated with 

 better methods, such as can now be de\dsed. 



Although, for several reasons, it is impossible to make a scientifically 

 justifiable classification of toxins, antibodies, etc., the arbitrary classifi- 

 cation here followed (see "Contents") has some logical basis. 



IRRADIATION IN VITRO 



VENOMS 



Snake venoms and allied toxic materials are complex solutions usually 

 exhibiting several properties in varying relative and absolute degree: 

 neurotoxic, hemolytic, or hemorrhagic, anticoagulant or accelerating 

 coagulation of the blood, and so on. Upon intravenous injection into 

 suitable animals in sublethal doses they are also capable of giving rise 

 to antivenins, and may, therefore, be said to act as antigens. The 

 hemolytic and hemorrhagic effects are probably due to cytolysis of 

 erythrocytes and capillary endothelial cells, respectively, and may be 

 due to a single ingredient of the venom. One and the same venom may 

 produce predominantly hemolytic effects in one species of animal and 

 predominantly hemorrhagic effects in another. If the cytolysis is 

 dependent upon the agent penetrating the particular cells affected, the 

 situation would be paralleled by such hemolytic agents as glycol, glycerol, 

 etc., which have similar specific relations with the erythrocytes of different 

 species (89). It is entirely possible that the neurotoxic effect, which 

 may be upon the respiratory center or the phrenic nerve which innervates 

 the diaphragm, or upon both, may be due to the same constituent of the 

 venom as the cytolytic effects, but there is no good evidence to support 

 this idea. In fact, Delezenne and Fourneau (42) believe that in the 

 case of cobra venom, a lipase in the venom produces a hemolysin in the 

 blood stream by acting upon lecithin to produce lysocithin, an extremely 

 hemolytic substance. The relationship between the coagulant, anti- 

 coagulant, agglutinative, and antigenic properties of venoms and the 

 cytolytic and neurotoxic effects is similarly obscure. 



Experiments purporting to show that, since heating or irradiation 

 causes the disappearance of one effect before another, these effects must 

 be due to independent substances, cannot be considered conclusive in 

 the absence of exact information as to the relation between venom 

 concentration and the different toxic effects which may vary differently 

 with change in concentration. 



For these reasons it is difficult to express on a sound quantitative 

 basis the effects of irradiation on different venoms as studied by different 

 workers using different criteria of toxicity. 



