VENOMS, TOXINS, ANTIBODIES 373 



irradiation after immunization is in progress may increase the titer of the 

 free circulating hemolysin in the blood, even if only temporarily. This 

 effect is perhaps analogous to the effects of injections of certain chemical 

 reagents such as pilocarpin on antitoxins (Salomonsen and Madsen, 139) 

 or MnCU on antitoxins (Walbum, 160) and hemolysins (Walbum and 

 Schmidt, 161). It is impossible with the information given to draw any 

 conclusions as to the dosages most favorable for demonstrating stimula- 

 tion or inhibition. 



There is no basis for concluding that hemolysins once formed are 

 directly affected in vivo by irradiation of any kind. 



Bacteriolysins, Phagocytosis and Opsonins 



Bacteria in blood may become incapable of colony production because 

 the plasma kills them or because under the influence of opsonins they are 

 ingested and killed by leucocytes. Although these may be independent 

 processes there are so many experiments which do not separate the two 

 that they are here considered as a group. 



Azzi (9) interpreted his experiments on guinea pigs as showing that 

 ultra-violet irradiation of infected wounds promoted both bacteriolysis 

 and phagocytosis; overexposure decreased the latter. 



Colebrook (35) observed an increase in the bactericidal power of blood 

 on exposure of normal and pathological men to sunlight. Since serum 

 did not show this change, he attributed it to an effect on phagocytosis, 

 but in a later paper with Eidinow and Hill (36) a slight effect on the 

 bactericidal power of serum was also claimed to occur in rabbits exposed 

 to ultra-violet light or other irritants producing erythema. Genner (69) 

 disagreed with these findings on serum and blood of ultra-violet-irradiated 

 rabbits and men, but Eidinow (50) appears to have presented fairly clear 

 evidence of the reality of the effect provided overdosage is avoided. No 



o 



significant effect was produced by light of X > 3100 A, unless eosin or 

 hematoporphyrin was injected to produce photodynamic effects; while 



o 



increases up to 65 per cent resulted when light of X 2500 to 3100 A was 

 used in dosages producing mild erythema. Bannerman (12) also 

 obtained results supporting the conclusions of Colebrook and of Eidinow. 

 The promotion of the bactericidal power of blood by ultra-violet 

 irradiation appears probable insofar as the production of substances or 

 conditions promoting phagocytosis is concerned, but doubtful with 

 respect to an increase in bacteriolysins. However, even the former is 

 subject to some reservation, since Pincussen (133) was able to observe 

 a greater proportion of phagocytes active in vitro after irradiation of 

 guinea pigs with infra-red or long-wave-length visible light (X > 7000 A) 

 while the visible and near ultra-violet portion of the light from the 

 "Vitalux" lamp, i.e., X 2800 to 7000 A, was inactive. Dark heating led 

 to similar results (cf. Liidke, 108). In Eidinow's and Colebrook's experi- 



