VENOMS, TOXINS, ANTIBODIES 355 



146) have also reported loss of specific precipitability by human serum, 

 and Hassko reports loss of precipitability by neosalvarsan for horse 

 serum, all as a result of ultra-violet irradiation. In the latter case, the 

 reaction was independent of free oxygen and was accelerated by passage of 

 bubbles of any gas. Some change of colloidal state is possibly the impor- 

 tant factor here rather than a chemical change. 



Anaphylaxis.— An animal which has received injections of proteins, 

 such as normal or antisera, may become sensitized so that further injec- 

 tions of the same protein bring on characteristic further symptoms of 

 what is called anaphylactic shock, which may lead to sudden death. 

 The injected protein may be considered to be an antigen, both when it is 

 used to sensitize an animal, and when it is used to induce anaphylactic 

 shock. 



The ability of proteins to sensitize animals seems not to have been the 

 subject of irradiation experiments. The power to induce anaphylactic 

 shock in sensitized animals is reduced by ultra-violet irradiation and 

 finally destroyed, but it appears to be more resistant than almost any 

 other immunological property of serum; only precipitability by specific 

 precipitins is more resistant (Baroni and Jonesco-Mihaiesti, 14 ; and Scott, 

 145, 146). 



ALEXIN 



Discussion of alexin or complement, as it is often called, will here be 

 directed first to the hemolytic function which is exerted in conjunction 

 with normal or specific hemolysins or amboceptors. There are over 

 20 papers dealing with this subject alone, more than for any other sub- 

 stance dealt with in this paper. At the end of the section brief reference 

 will be made to analogous cytolytic properties of blood and other body 

 fluids. Attention will be directed first to the effects of different types 

 of radiation on alexin, with brief reference to significant accessory details, 

 and then several papers having special theoretical bearing on the nature 

 of alexin and the process by which light inactivates it will be discussed as 

 a group. 



Observations. — Visible light, both with and without photodynamie 

 sensitizers, was found by Lichtwitz (105) to inactivate the alexin of both 

 normal and specifically hemolytic sera (rabbit and goat antibeef). This 

 is the first recorded photoinactivation of alexin. Lichtwitz found that 

 his "controls" lacking eosin were about half inactivated by exposure of 

 16 hr. to direct sunlight. An ice bath prevented undue heating, which 

 would alone have seriously affected the alexin in so long an exposure, 

 even if the temperature had been only 40°C. (Madsen and Watabiki, 

 113.) 



Bovie (23), in studying the effects of tropical sunlight on alexin, 

 maintained controls shielded from the ultra-violet of wave-length less 



