VENOMS, TOXINS, ANTIBODIES 351 



arc) and keeping his samples cooled to about 0° to 2°C., found both 

 diluted toxin and dry toxin exposed in very thin layers to be about equally 

 labile. The lability of the dry toxin is rather surprising. He also verified 

 a previous report, for which no citation is given, that ultra-violet irradia- 

 tion increases the ultra-violet absorption of the toxin. 



The fact that Schubert could inactivate tetanus toxin at 0° to 2° 

 conforms to expectations based on the theoretical and observed low 

 temperature coefficient of photochemical reactions. Cernovodeanu and 

 Henri (33) tested this particular point and found practically no effect of 

 temperature on the reaction rate between 0° and 24°C. The same 

 authors claim to have shown that the light reaction proceeds according 

 to unimolecular reaction laws, but the agreement is only approximate. 

 Welch (162), using an air-cooled carbon arc as a source of visible and 

 ultra-violet light, distinguished between the tetanolysin and tetano- 

 spasmin, but found them to be equally affected by light. 



Toxins appear to be very resistant to X-radiation. Lusztig (111), 

 in a paper which covers a great deal of ground, but which is marred 

 by omission of much needed details and by careless bibliography, states 

 that 10 H.E.D. ("Haut-Erythema-Dosis") had no effect upon the toxicity 

 (or pathogenicity) of (killed?) cultures of the organism of swine erysipe- 

 las (B. rhusiopathiae suis). 



No detoxication of tetanus toxin by radiations from radium was found 

 by Fabre and Ostrovsky (52, 53), although they did observe it in the case 

 of diphtheria toxins (see page 348). 



Toxin of B. hotulijius. — Gradual loss of toxicity of meat extracts in 

 which B. hotulinus had been grown was observed by Van Ermengem (159) 

 and by Thom, Edmondson, and Giltner (157) when the extracts were 

 exposed to diffuse or direct sunlight and air. 



The toxins investigated by Schoenholz and Meyer (141) required a 

 longer time for " inactivation " than those just mentioned, either because 

 they were originally more potent or more resistant, or because, as the 

 authors suggest, the layer of paraffin oil with which they overlaid their 

 toxic broth impeded the diffusion of oxygen into the broth and thus 

 retarded detoxication. 



Miscellaneous Bacterial Toxins. — Bacillus proteus yields a hemolytic 

 toxin when cultures are killed by ether, and the ether then removed 

 by aeration. This toxin preparation is probably susceptible to inactiva- 

 tion by visible light, although Ecker and Brittingham (49) found it to 

 be unaffected by the relatively very short exposure of 3 hr. which they 

 tried. It is about as rapidly inactivated by ultra-violet radiation as 

 other toxins, an "Alpine lamp" at 30 cm. reducing its titer to about 50 

 per cent in 5 min. In a very rough way, ultra-violet inactivation of this 

 toxin follows the exponential course of a unimolecular reaction, the 

 approximate observed toxicities after various exposures being 5 min., 

 • 50 per cent; 10 min., 25 per cent; 15 min., 5 per cent. 



