594 C. S. BACHOFER 



Lest the results of x-irradiation reported here be attributed to any partic- 

 ular or specific derangement requiring ionization as a cause, it should be 

 noted that, in general, all of the effects produced by ionizing radiation can 

 be duplicated with nonionizing radiation, provided only that the biologic 

 preparation be such that nonionizing radiation can penetrate to vital sites. 

 Just where these vital sites are, or what vital components are involved, is 

 not known. Current research in our laboratory indicates that certain com- 

 ponents of the metabolic mill may constitute vulnerable targets of radiation. 

 Such components may indeed be the affected entities, and their alteration 

 may be the basic seat of the altered function of the nerve. Observations on 

 membrane permeability, for example, may be valuable indicators of the direc- 

 tion in which we should look in seeking for more basic eflfects. To speak of 

 changes in permeability of the nerve membrane as the alteration responsible 

 for the altered function of the nerve (as we have done) may amount to 

 singling out one measurable manifestation which has its foundation in more 

 basic aberrations; it is, no doubt, the end result of a complex chain of 

 reactions. 



In conclusion, to leave the molecular level of interpretation for a possible 

 application at the systemic level, we might note in the present results that 

 there is a steady fall in conduction velocity at the same time that the spike 

 amplitude is rising. Such results suggest a neuronal basis for the immediate 

 lack of coordination and loss of equilibrium observed in animals subjected 

 to intense irradiation. Even delayed effects of irradiation, manifested in 

 various organs and systems, and of uncertain cause, may have their basis 

 in such neuronal aberrations as reported here. 



Summary 



The ventral caudal nerves of the rat, the median and lateral giant nerve 

 fibers of the earthworm, and the median giant axons of the lobster were 

 subjected to x-irradiation in vitro. The ventral caudal nerves of the rat were 

 also subjected to x-irradiation in situ. The giant fibers of the earthworm 

 were, in addition, subjected to UV irradiation. Various electrophysiologic 

 responses were observed before, during, and, in some cases, after irradiation. 

 Electrical stimulation was used to evoke propagated impulses, and measure- 

 ments were made of amplitude and rate of rise of the action potential, con- 

 duction velocity of the propagated impulse, sensitivity of the nerve to 

 stimulation, and relative refractory period. Photographic records of oscillo- 

 graphic traces were projected for measurement and analysis. 



The pattern of response for all nerves was essentially the same during 

 irradiation, whether the nerve was irradiated with x-rays or with UV. In 

 response to external stimulation during irradiation, all nerves showed an 



