VENOMS, TOXINS, ANTIBODIES 375 



They were unable by X-irradiation in doses of about "16 X" (about 

 3 H.E.D.) to affect this property of typhoid-immune rabbits. 



Precipitin 



Precipitin formation may be impeded or prevented by previous heavy 

 X-irradiation as shown by Benjamin and Shika (16); this was confirmed 

 by Hektoen (82). Benjamin and Sluka also observed that the injected 

 antigen disappeared v.ery slowly from the blood stream after irradiation. 

 They used single or divided doses of 60 to 100 H., i.e., about 20 to 30 

 H.E.D. Leidenfrost's (104) failure to observe any similar effects of 

 X-irradiation appears to be referable to the much lower dosage used, and 

 Lusztig's negative experiments (111) with exposures up to 10 H.E.D. 

 after immunization confirm similar findings by the earlier workers. It is 

 evident that X-radiation sufficiently heavy to cause heavy injury to 

 the reticulo-endothelial system interferes with subsequent antibody 

 production, but it has not been shown to have any marked effect on 

 antibody already produced. 



Agglutinins 



Visible and Ultra-violet Light. — Staubli (153) refers briefly to some 

 work which he did with v. Gonzenbach showing that at high altitudes 

 animals lost their typhoid agglutinin more rapidly than at low altitudes, 

 especially if exposed to svmlight. But this is probably misleading even 

 if generally true, which seems doubtful. Clinical and experimental 

 studies of the effects of exposure to a "Hohensonne" or similar source 

 of visible and ultra-violet light on typhoid-agglutinin titer lead to no 

 clear-cut conclusion. Hansen (72) reported irradiation to increase the 

 titer of the serum of tuberculous patients who had previously been 

 vaccinated against typhoid; and later (73) he obtained similar results 

 with rabbits. His experiments unfortunately are open to criticism as to 

 their statistical significance. Bessemans and Seldeslachts (19) , confirming 

 Hansen, and Konrich (99), failing to confirm, are, as mentioned above, 

 both of quite reasonable statistical validity, and their diametric dis- 

 agreement is difficult to explain. A possible clue lies in Potthoff and 

 Heuer's experiments (134) in which colored animals showed an increase, 

 and unpigmented animals a decrease, as a result of daily irradiation during 

 the development of immunity. Conditions affecting the amount and 

 spectral distribution of the light reaching the capillary circulation may be 

 a maj or disturbing factor. On the whole it seems likely, though unproven, 

 that irradiation of this general type can, under the right conditions, 

 promote high agglutinin content of the serum. 



Berntsen's finding (17) that agglutinins against B. tuberculosis were 

 increased in the sera of surgical-tuberculosis patients upon irradiation is 

 based upon rather slender evidence. 



