VENOMS, TOXINS, ANTIBODIES 357 



of the serum in which it was suspended, and correctly interpreted the 

 effect as due to screening. 



The principal contribution of Delbet and Beauvy (41) was the nega- 

 tive one of finding no correlation between alexin destruction and the 

 appearance of the ultramicroscopically observed particles in the serum. 

 These particles showed active Brownian movement and negative cata- 

 phoretic charge. Normal human serum, which is hemolytic for rabbit 

 erythrocytes, was used. This serum possesses not only the alexin 

 property, but also another substance, a "normal hemolysin" necessary 

 for hemolysis (cf. page 365). Only the alexin was inactivated in Delbet 

 and Beauvy's experiments, the hemolysin being more resistant to 

 irradiation. 



Friedberger (66), keeping his samples on ice during irradiation, was 

 unable to inactivate the alexin of dried and powdered serum, but did 

 inactivate alexin in solution. He also experimented with " M " and " E " 

 fractions ("mid-piece" and "end piece") of alexin obtained by Lieff- 

 mann's method. The separation was undoubtedly very incomplete, 

 and in view of much better work by Schubert (142, 143) need not be 



discussed. 



Neither Scaffidi (140) nor Heuer (85) added anything new in regard 

 to ultra-violet irradiation. The same is true of Brann (24). Baker 

 and Peacock (11) make an interesting estimate of the relative sensitivity 

 of alexin and B. coli, the alexin being about 20 times the more rapidly 

 destroyed by the light of a 70-volt 3-amp. Cooper-Hewitt quartz-mercury- 

 arc lamp. 



Diacono (43) showed that the specific hemolysin in the serum of an 

 immunized guinea pig was more stabile than the alexin of the same serum 

 when exposed to ultra-violet Hght. Delbet and Beauvy had previously 

 shown the same for a normal hemolysin in human serum. 



X-rays and Radium Rays. — The earlier reports of attempts to inacti- 

 vate alexin by X-rays (58, 62, 140) are alike in their failure to find any 

 effect and in the absence of any description of the type or dosage of 

 radiation which gives any satisfactory idea of these factors. Fiorini and 

 Zironi come the nearest to such a description when they state that the 

 source was a "demimous" tube at 10 cm., and the dosage "5-lOX." 



Schubert (142) gives a somewhat better but still meager description 

 of his source, and reports slight alexin inactivation in 1 hr. He used a 

 Coolidge tube, voltage and current not stated, and filtration through 

 1 mm. Al. Merlini (119), on the other hand, did not find any alexin 

 destruction by X-rays. His dosage amounted io^ie to i^ skin erythema 

 dose and the conditions described suggest that he used "harder" radiation 

 than did Schubert; this may account for the disagreement. 



Lusztig (HI) is able to give a much better description of his source 

 and dosage, the latter being given in terms of H.E.D., 1 H.E.D. being 



