344 BIOLOGICAL EFFECTS OF RADIATION 



in other systems and will be discussed below in relation to the photola- 

 bility of tetanus toxin. 



Arthus and Collins studied also the influence on coagulation exerted 

 by venoms as affected by ultra-violet radiation. In vivo cobra venom 

 retards coagulation, while the venoms of the daboia, the fer-de-lance 

 (Bothrops atrox) and the tropical rattlesnake (Crotalus terrificus) promote 

 coagulation and lead to thromboses. In vitro the effects of the first 

 two on citrated plasma appear only on addition of calcium ions, coagu- 

 lation being then retarded (cobra) or accelerated (daboia), while the 

 last two are alone able to coagulate citrated plasma. Ten minutes' 

 irradiation, the temperature not exceeding 25°C., was adequate to reduce 

 all these types of effects to 5 to 10 per cent of their original strength. 

 Data are given for various times of irradiation, and a fairly complete 

 picture of the progressive effects on the different venoms may be 

 obtained. 



Phisalix and Pasteur (129) have made an extensive study of the 

 effects of ultra-violet irradiation on the venom of the European asp 

 (Vipera aspis). The 400-watt quartz-mercury-arc lamp, emitting light 

 down to 2300 A, was not sufficient to affect significantly the toxicity 

 of this venom (1:1000 in physiological salt solution) as judged by its 

 effect on mice. The authors suggest that there was perhaps a slight 

 increase in toxicity due to irradiation, but this is not borne out by the 

 data given. The irradiated venom was, however, not capable of pro- 

 voking immunity, so that the antigenic power ("echidno-vaccine" of 

 the authors) was destroyed by irradiation which left the neurotoxin and 

 hemorrhagin essentially unaffected. 



Viper venom is also capable of destroying the virus of rabies in vitro 

 even after heating to 75°C. for 15 min. to destroy its toxicity; this power, 

 as well as its immunizing properties, is destroyed by heating to 100° 

 for 10 min. (Phisalix and Pasteur, 130). Viper serum has similar prop- 

 erties, and irradiation of serum destroyed the antigenic and antirabies- 

 virus properties while leaving the toxicity unaffected (Phisalix and 

 Pasteur, 131). 



Destruction of the toxic properties of viper venom (Vipera aspis f) and 

 cobra venom by exposure to the radiation from a capsule of RaBr2, was 

 observed by C. Phisalix (127). Presumably the effect was due to 

 gamma and perhaps also beta radiation, but the description of the experi- 

 ments is too meager to allow closer analysis. RaEm and its active 

 deposit dissolved in the venom solution also inactivated it, in this case 

 with development of turbidity and a characteristic odor, perhaps as a 

 result of alpha and increased beta radiation (128). 



C. Phisalix (128) also found the poisonous secretions of a terrestrial 

 salamander and the common toad to be unaffected by radium radiation 

 in similar dosage. 



