VENOMS, TOXINS, ANTIBODIES 367 



containing 20 to 24.6 mg. RaBr2 being suspended in, or close to, the sera. 

 No information is given as to whether alpha rays could reach the sera or 

 not. This lack of information also vitiates the experiments of Fried- 

 berger and Shiga (68) who used 85 mg. of RaBr2 "in a metal capsule in 

 needle form 2 cm. long" (translation mine). These authors claim to 

 have found some weakening of syphilitic antiserum, the process continu- 

 ing after the end of irradiation. But the omission of essential details, 

 such as the composition of the radiation incident on the serum, robs both 

 of these papers of most of their meaning. 



Other complement -fixing antibodies have been shown to be destroyed 

 by ultra-violet irradiation in vitro, e.g., cholera antiserum [Baroni aiwl 

 Jonesco-Mihaiesti (13) J. 



Precipitins may be thought of as antibodies which form a visible 

 precipitate instead of the supposed compound or amicronic precipitate 

 responsible for alexin fixation. This property is destroyed by photo- 

 dynamic irradiation, according to Fleischmann (60), and possibly also to a 

 very slight extent by visible light alone. He also considered that oxygen 

 may be essential, but this point was left unproven. The precipitins 

 tested were rabbit sera precipitating beef or horse sera or egg white; 

 sensitizers were eosin or safranin, 0.5 per cent, or methylene azure, 

 0.01 per cent; 8 hr. illumination resulted in complete inactivation. 

 Fleischmann also showed that irradiated precipitin, even if incapable of 

 producing a precipitate, still combined with or otherwise so affected 

 the precipitable substance that it could not be precipitated by the addi- 

 tion of nonirradiated precipitin. When the precipitable substance was 

 irradiated a similar situation resulted. 



Doerr and Moldovan (44) also used rabbit anti-egg white serum, and 

 found it to be inactivated by a few hours' ultra-violet irradiation from 

 a Kromayer quartz-mercury-arc lamp. The first effect of irradiation 

 was more in the nature of retarding precipitate formation than of reducing 

 the amount; but in time the amount of precipitate formed was also 

 reduced and finally no precipitate formed. The proper understanding of 

 this retardation effect is important for titration of irradiated precipitins. 



Lusztig (111) was unable to affect rabbit anti-horse serum albumen 

 precipitins by X-radiation up to 10 H.E.D. 



Agglutinins are antibodies which precipitate bacterial or other cells, 

 and are, therefore, related to precipitins. There seems to be no record 

 of their inactivation by visible or photodynamic irradiation, but pre- 

 sumably this would occur since they are easily affected by shorter wave- 

 lengths. This was first shown by Dreyer and Hanssen (46) who made a 

 special study of the course of the inactivation process. Table 2 shows 

 the extraordinary agreement which they found between experiment and 

 theory, assuming the reaction to follow a unimolecular reaction isotherm. 

 Unfortunately they do not describe their method of agglutinin titration, 



